I put my acetone in a quart jar so that I could get it out easier and faster.So I mixed my anhydrous magnesium sulfate real good and slapped on the lid and let it settle.So today I was going to go ahead and mix the fumaric acid but when I pulled the lid off the rubber was hanging all off and melted.The thing is that I even poured a little acetone off so that it wouldn't make contact with the rubber.I'm pretty sure that it never made contact which leaves me with the question whether the fumes had done this.Is it still good to use?

As long as no rubber actually got into your acetone you should be fine. I would also advise changing to a different container.

yea the fumes do dry out lids

Thanks for the reply.I kinda figured that it would be okay but wanted a second opinion on the mater.What would you suggest switching it into?

Either some HDPE if your not going to keep it for any real length of time
or
you could still keep it in your quart jar and use some foil or something to cover it, after all acetone fumes are heavier than air - if it is a screw top lid then just clear out the rubber and use it without the rubber seal.

Aha Why didn't I think about that first.I tell ya I really need to start to think for myself sometime instead of looking to yall guys to answer all my questions lol.Any way thanks yall