I'd clean off the mold, then I'd eliminate the first half inch or so of jelly. Then, I would either eat just a spoonful and wait to see if my stomach wracks with pain after a while... or I'd just eat it and not worry about it. Maybe depends on what kinda jelly it is, too... if it's got chunks of fruit in it, maybe hesitate... if it's just all clear color all the way through, then what the heck.