Anti Slip What Is The Best Way To Remove The Residue From Those Old Rubber Stick On Anti-slip Mats From Your Tub?

What is the best way to remove the residue from those old rubber stick on anti-slip mats from your tub? - anti slip

The house I bought an old bathtub, which has the "lagging behind" many of which he caught in rubber anti-slip mats on the floor of the tub. The former owner removed the rubber mat, but what is left of the glue and dirt adheres. I tried Clorox, washers and dust from steel wool, whatever. Unless, of course, a mill and / or finishing of the tub, each has a proven way to eliminate this unsightly mess? Thank you!