That sounds like the flakey stuff that gathers in the kids bath toys.. they have the toys that water can go into and we squeeze out the yucky looking brown flakey things.. which im not too sure what they actually are, but they are water related, like abuild up of the water somewhere... i have thrown out so many bath toys because of it!!

i would say it is something like that in your washing machine and it needs cleaning out somewhere!! Good luck!!