When this spring rolled around, I grabbed a bottle of #9 to buff out a friend's hood, only to find that the product had turned completely to liquid. Same thing with my tube of ScratchX. Both are around 3 years old (I don't use the #9 all that much) and both spend the winter in my unheated garage.
Did the time or the conditions cause the liquification?
Aside from the obvious mess factor, does the effectiveness of the product degrade when in liquid form?