... hot fudge, and chocolate syrup are all fine if...
When the scum stops appearing pour the syrup back into a clean bottle and keep it in the fridge.
Cough syrup. If I don't drink a mouthful before going on stage I can't settle down!
Part of why corn syrup is in everything is because massive corn monocultures have created a surplus that agriculture companies are scrambling to get rid of.
The other part of why corn syrup is in everything is that it's cheap.