For what it's worth, I use mine until they are pretty gray. If I'm really worried about the fabric running I will throw in an extra one.

I use them when prewashing my fabrics, but hadn't really thought of reusing them. I will have to give that a try, thanks!

Thanks, everyone! I didn't know this either!

I've found mine at the Wal-Mart supercenters and at Target.

I can only get them at walmart or the base commissary!

re-using for laundry, do not know. heard that some were putting the "used" for backgrounds in their fabric post cards.

I've used them more than once, and when they come out white, I dry them by putting them flat on the dryer. I'll use them till they come out pink or colored darker, then toss them.
Better to be safe than expensively sorry.

I have re-used the ones where the fabric didn't do much bleeding. I make sure they don't go in the dryer.

I get mine at Walmart or Kroger

they came out green this time..so out they go! used them three times though!