I have been making cakes for about 2 years and have never had my fondant/GP mix to turn really sticky and lumpy when I store it. If I have some left over, I store it in plastic wrap then in a zip lock bag.  But when I get it back out a few weeks later it's really, and I mean really, sticky and lumpy and nothing will get it back to it's normal consistency.  Has anyone had trouble with this happening?? I never had problems with this in the past, it started last year.  I use Wilton GP and either Wilton fondant or MMF.

After wrapping it in plastic and placing it in zip lock, where do you store it? I store everything (GM and fondant) in the ref. What is the weather like in your area? I live in a high humidity country, I don't take chances I shove everything in the ref. The only thing I know that will make fondant and GM sticky is the presence of any water or moisture.

AI live in GA and I store it in my basement storage room which is heated. You may have a point though, I just remember I had my basement finished about a year ago and I started storing my cake decorating stuff down there. And a year ago, there abouts is when I started noticing it getting sticky/lumpy. I'll put it in the fridge and see if that fixes the problem. Thanks for the help Mintbelly.