Claire, they're fully washable
if you put them in the washer (I do this with my sew-in labels before I even cut them apart) on hot, wash them, dry them in the dryer, they'll be fine.
If you spot-clean, or if you get them wet and let them sit, or even if you let them hang-dry after washing, the colors may run or bleed.
This goes for most heat-transfers
So I'm "rough" with my stuff and put them through the dryer :P
As for "how this works".... if you want the image I will format it for you to fit as many as possible onto one 8 1/2 by 11 sheet. Then I'll send you a .PDF file to make sure it's a nice and crisp print quality. The file might be large, but the quality is superb!
I'll send it out in a little while, have to make ice-cream with my sons LOL.