don't scrub, it wont make it any better, if anything itll be worse
if you want you can pull the rock out, and burn the aip off with a lighter or something like that.
theres also aiptasia X (used it and dont recommend it) and joe's juice, if its cycling id suggest boiling some water, putting it in a turkey baster, and squirting the bugger with it in the tank, or inject it with some lemon juice, there are plenty of options. just google it lol