Some of the scotch-brite pads, the wavy sponge with the pad attached, come loaded with a cleaner to keep the sponge from drying up- if you put it under tap water and squeeze it a few times it will get a bit sudsy. the 3m pads by themselves should be fine, and you can actually get them in different abrasive grades (used in the automotive industry for scuffing substrate for paint). The red ones will not scratch glass.
I found sometimes soaking a tank in vinegar is not practical- for example you'll need a few gallons of the stuff to soak a mineral coated hood in. You can just take a rag or something, soak it and then apply the rag to the area. I always had problems with the vinegar drying out before it did its job on the tough spots, this will keep that from happening.