I bought a pair of silpat mats approx 2 years ago. I make cookies maybe 3-4 times a year and except for Xmas never more than a 2 batches at a time. At Xmas I probably make 6 batches at a time over a number of days.
I always wash my mats with a sponge using warm soapy water , hang to dry and then store them loosely rolled w/ a rubber band on a pantry shelf. Well I have not made cookies for at least 3 months and tonight I get out the silpats and they feel greasy and icky. I know that I washed them the same as always before I put them away so I can not figure this out. So I wash them again with a sponge and soapy water, rinse well and they still feel really greasy, slimy almost. So I try soaking them in hot soapy water and then use the scrubby side of sponge to really scrub them down and they are better but only a little bit, they still feel really greasy. So now I am wondering do they just "go bad" after a while? Any advice?