While it looks like there is a variety of successful approaches, I think the reason some have success with one approach and others don't is the nature of the stains. Some stains are simple body oils stuck in the texture of the nonslip pads. Using something alkaline like shampoo should work for those to soften the stains and allow them to be scrubbed lightly. WD-40 should also dissolve those and lift them. Other stains are based on hard water build up of calcium. The calcium can't be seen because it is white but the calcium will catch and hold the body oils. If you cannot get the calcium off, the stains remain. This is where an acidic approach would work. Barkeeper's Friend is oxalic acid with a mild abrasive. If the stains are calcium based, this should wash them away very easily. I would like to suggest another approach to the plain body oils with no calcium build up. There is a cleaner used in the automotive detailing industry called Super Clean. It comes in a purple spray bottle at auto stores, hardware stores, Walmart, etc. It is basically 409 on steroids. If you have trouble breathing when using 409, then you will really have trouble breathing around Super Clean. I bought some for my car and, of course, it works great. Then I read the label and decided to try it in the kitchen. The first thing I tried it on was burned on grease on a stainless pan - the bottom of the pan. I sprayed it on and let it sit for a "dwell time" of 10 minutes. Then I ran hot water from the faucet into the pan and 99% of it just rinsed clean with no scrubbing. I thought maybe I had a pan with grease that looked burned on but was just sort of already softened, but no. I tried it again and again with the same results. So that is my experience with Super Clean. I thought someone might give it a try on their tub texture spots and report back here with results.

Thanks. The more I think about it, the more I think adhesive would be a good choice--I'd prefer that over staples or nails since I recently painted the stairs and wouldn't want to put a ton of new holes in them. But this would be a much safer, more permanent method than trying to find a truly non-skid backing. Do you have any adhesive recommendations? Thanks again.

I've never had any problem with tile but would not use on wood. I moved into a house once where the finish on the wood floor in front of the sink had been damaged by a rug. I currently have some rubber backed rugs on the vinyl flooring in my laundry/back entry but it's not a color that you'd ever notice discoloring plus it will always have some kind of rug there. I always get the thicker area rug type rugs that have the woven back for places that I don't want rubber backing. I don't care for the thinner rugs with no backing because they don't stay flat and are a tripping hazard. I get a color that doesn't show every little thing and get them professionally cleaned once in a while.

I was interested in this, too. However, if you read the FAQ, it only claims to alter the tile's coefficient of friction when wet. It says it will not change the slipperiness of the dry tile. I am debating using some epoxy grout, and just not cleaning it up off the surface totally. Any thoughts on that harebrained idea?