I have a jar of real fruit jam, made without pectin, it tastes fantastic but the berry seeds are extremely hard. Can I reheat it in a pot on the stove and strain out the seeds and put it back in the jar and keep it refrigerated?
For a jam, (assuming with fruit solids), be aware that since you will have to force it through a strainer whether you warm it up or not, it will lose some of it's fruity texture. But it will taste the same. It will be easier if you warm it, but do NOT let it get hot enough to steam or bubble. And yes, keep refrigerated.
My reference is 65 years of making my own.