Just to add....
Like said, sealing non-skid starts with getting the entire surface of the non-skid clean and that's the tricky part because of the grid style textured surface.
Most people that know me in the automotive world no I do everything I can by machine for a host of reasons. In the marine world I'm the same way. If I can do a job by machine I'll do it versus working by hand and this holds true for cleaning non-skid.
Cyclo makes a variety of brushes for their Cyclo polisher that will also attach to the Porter Cable style dual action polishers and these brush work GREAT for really getting the non-skid clean by machine.
Check out this thread as it has a bunch of pictures showing these brushes in action.
Ship Shape TV - Cleaning non-skid surfaces by machine with Marine 31 Port to Starboard APC
For what it's worth, I just used the white Cyclo brush with an all purpose cleaner to scrub clean the non-skid floor in both our shower stalls at home.
Even took some before and after pictures.
