Washing a backpack is one of those jobs that gets postponed until the bag smells, and by then the problem is at the bottom of it, under a layer nobody has looked at since August. Most bags can be cleaned properly in an evening. A few should never go near a machine at all, and telling those two groups apart is the whole job.
Empty every pocket, and that means every pocket
Bags have more compartments than anyone remembers, and this step decides whether the rest goes well or badly.
Open every zip, including the one on the hip belt, the pen sleeve, the pocket behind the back panel and the one in the lid nobody uses.
Turn it upside down and shake it hard over a bin, then run a hand into each corner, because grit sits in the corners and shaking does not move it.
Look for pens, lip balm, coins and anything paper. A pen that goes through a cycle marks the lining permanently, and that is the most common way washing a backpack ends badly.
Vacuum the inside if you can. Getting dry grit out before water is involved saves trouble, because wet grit becomes a paste that works into the seams.
Check the outside pockets for forgotten fruit. It happens more often than anyone admits and it is usually where the smell is coming from.
The bottom of the bag is the worst part
If a bag smells, the smell is almost always in the base, for three reasons.
Everything falls to the bottom. Crumbs, spilt drink, grit off a floor and whatever leaked out of a container all end up in the same few square inches.
The base is usually a heavier coated fabric with a bound or taped seam, which holds moisture and does not breathe.
It is also the part that sits on the ground, on tarmac, on a changing room floor and in the footwell of a car.
So most of the effort in washing a backpack belongs there. Turn it inside out if the lining allows, work the seams with an old toothbrush, and push detergent into the corners rather than across the flat faces.
A bag cleaned everywhere except the base will smell again within a fortnight.
Spot cleaning against a full wash
Most bags do not need a full wash most of the time, and a full wash is not free in terms of wear on the fabric and the hardware.
Spot cleaning is right for a specific mark, for a bag with a rigid frame or a moulded back panel, for anything with leather trim, and for any bag whose maker says not to submerge it.
The method is warm water, a little mild detergent and a soft brush, working in small areas and blotting rather than soaking. Follow with a second cloth and plain water, because detergent left in fabric attracts dirt straight back.
A full wash is right when the smell is general rather than in one place, when something has soaked through the lining, or once or twice a year on a bag in daily use.
Do the emptying, brushing and spot treatment first either way. Washing a backpack does not remove a set mark that was never treated.
Whether it can go in a machine at all
Before washing a backpack in a machine, look for a label. A surprising number of bags have one sewn into an inside seam.
The clear no list is rigid internal frames, moulded plastic back panels, leather or suede, wheeled bags, anything with a wired battery pocket, and anything with a foil or foam insulated lining.
The usually yes list is plain fabric school bags, canvas and nylon daypacks, drawstring PE bags and most soft kit bags.
The maybe list is anything with a printed panel or a heavy applied logo, which can crack or peel, and anything with a stiffened foam back panel, which survives a wash but dries slowly.
Hand washing in a bath or a large sink is the safe middle option, and it takes about twenty minutes.
If you are still in doubt, spot clean. A bag that is clean but slightly marked beats one with a back panel coming apart.
Washing a backpack in a machine without wrecking it
The precautions matter considerably more than the cycle settings do.
Empty and brush it out first, then pre treat any marks and give the treatment time to work.
Turn it inside out if it will go, then fasten every buckle and close every zip. Loose straps wrap around the drum and loose buckles crack against it.
Put the whole bag inside a mesh laundry bag or a pillowcase tied shut. That step protects the straps, the zip pulls and the machine equally, and it is the difference between washing a backpack and slowly destroying one.
Cold or cool water, a gentle cycle, mild detergent and a small dose. A bag has a lot of surface area and rinses poorly, so anything excessive stays in it.
No bleach and no fabric softener. Softener coats the fabric, leaves a residue that holds dirt, and degrades whatever water resistant finish the bag started with.
Wash it alone or with a couple of old towels for balance, and use a low spin, because a high spin on a bag full of padding throws the load out of balance and strains the seams.
Straps, zips and the parts that fail first
A bag is rarely destroyed by water. It is destroyed by hardware moving against a drum for forty minutes.
Buckles crack, adjusters bend and zip pulls snap off, and all of it is prevented by the mesh bag and by fastening everything first.
Straps fail at the stitching where they attach rather than in the webbing, and a soaked bag hung by one wet strap is the wrong way to treat that stitching.
Zips want rinsing rather than scrubbing, and running them open and shut a few times while damp clears grit out of the teeth.
Coated zips and taped seams do not tolerate heat, which is one more reason nothing in this job involves a dryer.
If there is a hip belt or a sternum strap, clip them closed rather than leaving them loose.
Air drying, and why the padding decides everything
This is where washing a backpack usually fails, and it fails invisibly.
Foam in a back panel and in shoulder straps holds a great deal of water and dries from the outside inwards, so a bag can feel dry on the surface with wet padding inside it.
Never use a dryer. Heat warps plastic frames, softens coated fabric, shrinks a lining away from the shell and finishes off any water resistant treatment.
Press the water out with towels first. Lay the bag on a towel, roll it up and press rather than wringing anything.
Hang it upside down with every zip and pocket open so water runs out of the base, and get air moving across it. A fan does more than warmth, because moving air is what dries foam.
Give it a full day, longer for a heavily padded bag. Squeeze the straps and the back panel before calling it done, and if they feel cool and heavy they are still wet.
A bag put away damp will smell again within a week. More of the value in washing a backpack sits in the drying than in the wash.
Lunch bags, kit bags and PE bags
These need weekly attention, and they need different handling from a backpack.
An insulated lunch bag with a foil or foam lining should be wiped rather than washed. Warm soapy water on a cloth, plain water on a second cloth, then left open to dry with the zip undone.
Crumbs collect in the seam where the lining meets the zip, and that seam is basically the whole job. A toothbrush is the right tool.
A drawstring PE bag is ordinary fabric and goes through a normal wash with the clothes. It is the easiest item here and the one most often forgotten.
A kit bag carrying damp gym clothes needs emptying the day it comes home, because kit left sealed in overnight puts its smell into the bag and the bag hands it back.
Leave every bag in the house open rather than zipped when it is not in use. A closed empty bag with moisture in it will smell, and an open one will not.
The Phoenix part
Three local factors change how a bag behaves here, and two of them are in your favour.
Fine dust is the first, and it is why bags here want emptying more often than the smell suggests. Grit gets into every seam and settles in the base, and it does not rinse out easily once wet, because damp dust becomes a paste that sets in the stitching. Shake and vacuum before any water is involved.
The dry air is the compensation, and it solves the hardest part of this job. Foam back panels and padded straps are slow to dry anywhere, and low humidity means a bag hung upside down in front of a fan is genuinely dry in a day rather than three.
Desert heat is a thing to avoid rather than to use. It is tempting to leave a wet bag in a car or in full sun to speed things up. Direct sun fades printed panels and breaks down the coating on nylon, and a closed car in summer gets hot enough to warp plastic buckles. Shade with moving air beats sun without it.
Water hardness is the last factor. Mineral rich water leaves a chalky film on synthetic fabric that holds dust and makes a bag look grubby soon after cleaning. A small detergent dose and a thorough rinse handle most of it, and a final rinse with a little white vinegar cuts the film.
Where a bag washes away from your clothes
A bag wants its own machine and plenty of water, because what comes out of one should not be going through your next load of clothes.
The machines at our self-service laundry on North 16th Street move enough water to rinse grit out of a bag properly rather than redistributing it, and a separate drum keeps the dust and crumbs away from everything else you own.
Our machines and the store are cleaned daily.
Our wash-dry-fold service covers the everyday laundry.
For general guidance, The American Cleaning Institute publishes a fabric care guide that is a useful cross-check.
The short version
Empty every pocket, shake the bag out and vacuum the inside before any water touches it, because wet grit turns to paste in the seams. Concentrate on the base, which collects everything and holds moisture. Spot clean anything with a rigid frame, a moulded panel, leather trim or an insulated lining, using mild detergent and a second cloth with plain water. If the bag can go in a machine, fasten every buckle and zip, put it inside a mesh bag or a tied pillowcase, and run a cool gentle cycle on a low spin with no softener. Then hang it upside down, fully open, with a fan on it, because washing a backpack is only finished when the padding is dry, and that takes a full day.
WaveMAX Phoenix on North 16th is at 2825 N 16th St Suite 1, easy to reach from Phoenix and the surrounding area. If you have a load that will not fit at home, call us at 602-314-5706.