I make a paste of baking soda and water to put on the bad areas then let it sit overnight. The next morning I rub it around to make sure all of it is loose then wipe it up. If there are a few spots left, I repeat. Wishing you the best.
Hello Linda: What I use is a paste of vinegar and cream of tartar (the dry stuff). Make a paste and put it on the gunk. Let it sit for about 15 or 20 seconds and then scrape off with a plastic putty knife or one of those plastic scrubbies. You may have to do it a couple of times if the gunk is thick, but usually not. There is no smell and it is environmentally safe. Good luck.
Try Krud Kutter original concentrate. Do not dilute. Put on let I it set for a bit, wipe off. May have to do a couple of time. A friend used soft scrub without bleach and a scrubbie and elbow grease.