I bought some tomato preserves from a really funky so-called produce stand. The lid is a bit rusty and the label appears to have been wet (along with everything else in the store). The jar is tightly sealed. It is my contention that the contents are fine, since the sugar acts as a preservative, but my husband is skeptical and suggested that I reheat the preserves just to be sure. Will they re-congeal if I do that? Tomato preserves are hard to find.