This happened to our floor in the laundry room. The floor under the freezer turned dark yellow. The floor guy said nothing can be done to get rid of the discoloration so we replaced the floor with ceramic tile.

I had this in the bathroom when I moved out of my house. Yup, I had a non-slip rug and it was yellowed underneath. I had to replace the vinyl before listing the house for sale. It also happened underneath the washing machine. I left the washer and dryer in the house so didn't have to deal with it.

I would try making a paste from some oxy clean powder and water and let it sit overnight, then wipe it away and see if that works.

Mine is yellow where everyone comes in thru garage and where dogs have missed puppy pad. I can't say I know ehat to clean it with, I will try Ammonia.

Give up. Replace. Nuff said. Been there.
sandy

If its around the rug and not underneath where the rugs was located... it is likely its from the oils on shoes that come from a black top driveway. Blacktop will continue to give off an oily residue ..enough to discolor high traffic areas of vinyl flooring.

I have the same issue around the perimeter of my kitchen cabinets but not that 3 inches under the cabinets. I was baffled at why this would happen. Logic would indicate the area under the cabinets would discolor as it might not get cleaned as well. When I really examined where the area was that was most affected it was in front of the refrigerator ( of course) in front of the sink... but the area were I stood the least had no yellowing.

A flooring person clued me in when I was researching what kind of floor to replace it . He asked me "do you have a black top driveway and leave your shoes on when you come in the house?" I said yes and he told me the last thing to consider is vinyl or I will have the same problem.

Just to further investgate .. asked my neighbor with a concrete drive way if he had yellowing of his floors... NOPE , no issue .

Do you have any of the vinyl left from when it was laid? I would cut out the problem and glue down a piece. Or put a rug over it as suggested. We tiled over ours.