I have some "scum" around the water line of my tub...it is sort of sticky and hard to get off.....(I have since changed out my filters and added a scum bag..) However I need to clean off the waterline of the tub. Any suggestions on how to best do this? I tried a sponge, and a magic eraser but this stuff on the waterline is SUPER hard to get off..I almost need to use my finger nails to get it off. I didn't know if I should use vinger and/or arm and hammer baking soda since I wasn't sure if it could mess up the water if any of it got in there...
Any suggestions? Is a tooth brush safe to use?