You can also get MUCH stronger vinegar at Home Depot.  Regular vinegar is like 4% vinegar.  This stuff is about 30% vinegar... don't let your nose get near it!!!  As noted, gotta let it sit for a bit.  If not, go to the 4-ott steel wool - although I personally use bronze wool simply because you won't get those annoying scraps of steel wool that leave tiny little rust stains.