My customers occasionally ask me how they can clean their vintage vinyl floorcloths. With heavy use, like I have here in the store, the dirt can get into the grooves which make the vinyl a non-slip surface. White areas might show the dirt more prominaltey. What works for me is actually very simple. I spray a bit of multi-purpose surface cleaner like 409 and let it sit for a minute. Then used a soft cloth and hot water to wipe it. A little bit of pressure and elbow grease and the dirt comes right up! Remember not to use harsh abrasives like Comet or hard brushes on your vinyl. You can see the results in the pictures. I did a spot area (red arrow) so you can see the difference.