you can tie-dye anything. yes your cat. :)
i did this when i did my flats. :P
Get in the car and drive to micheals/hobby lobby/said craft store.
Take your bag, wrap it up in any style/way. and tie dye! :D
If your bag has handles like mine, they will stay white [the dye came out] so if they arent a sort of plastice weave make sure if you want to dye them or keep them white. if you want to keep them white and they are made of cloth. i suppose you could duck tape over it but i havent tried. that is a bad picture of my handles
put in a bag, let sit like the instrutions say on the tie-dying box, then wash according to instructions.