you mean back packs right     garbage can  washing won't get the smell out
of the fabric

1) Wash it and use a little baking soda with the detergent and use vinegar
in the rinse cycle.

2) Never leave bags on the floor.

3) Buy a new bag.

I had a student in class Wednesday, (I Sub so have a variety of classes)
whose shoes smelled of pee, not of dirty feet, but of pee.  So at least your
bags don't get a regular dose of pee unless they are left daily on the
floor.