I have some left over from a cake this past weekend and was thinking of using it for some cookies this weekend. Anyone know? Thanks!

I have kept it for two weeks. I kept it in the fridge, and it tasted fine. I think it would be okay. I mean, it is basically marshmallows, crisco and water, nothing that would spoil. But, I could be way wrong. I will keep watching this topic, I would like to know other's opinions.

I agree it should be fine. As long as it hasn't dried out. If it seems hard, MW it for a few seconds to soften it up.

I keep it for months, crisco'd and double saran wrapped and then in a ziploc to boot. I just this past weekend reused some fondant from 2 months ago.

That is great to know - I have a batch I made a couple of weeks ago and I was about to throw it out. I, too, crisco and double wrap it. It looks like I will be using it on the cake for this weekend. Yay!

I love this stuff. I made a batch a month ago and am still using it. I am a big fan of MWing it too. I have a bum wrist and if I stick my wad of MMF in the MW for 5-10 sec, then knead in the color, it is sooooo much easier. But be careful not to overdo the heat, cause it'll just melt and be a mess.

I use my FoodSaver and I've kept some for a few (2-3?) months!