In Harry Potter and the Half-Blood Prince, Snape says (through Demelza):
And he wanted you to know you'll be sorting out rotten flobberworms from good ones, to use in Potions and — and he says there's no need to bring protective gloves.
However, as far as I know flobberworms are harmless. In fact in Goblet of Fire, Harry says that flobberworms don't even have teeth:
"What's this rubbish about him" — he pointed at Crabbe — "getting a bad bite off a flobberworm? They haven’t even got teeth!"
So why would protective gloves be necessary for handling flobberworms? Is it simply because of the slime?