Cleaning and Stain Removal - Stained kitchen counters

We bought a home that was rental property, and needs a bunch of fixing up.
The kitchen counters are a plastic laminate, I would guess. The edges on some parts are coming unglued.
Anyway, parts of them have a brown or yellow stain that I have been trying to get out. I washed, scoured, rescoured with cleanser powder, and even went back and tried a water bleach mix. Nada
The counters will be replaced down the time frame, but right now we want to just leave them as is, sans the stain.
Anyone know anything that might help take out the stains?
Thanks in advance
Sarge

Abrasives will damage the plastic laminate surface. The yellow stains may be from heat damage or chemicals, which means that they may be permanent stains. If spraying on a household cleaner like 409 and giving it time to lift the stain does not work, then it is likely the stain is permanent. A last resort would be to try some bleach. Again, stains secondary to heat and chemicals tend to be permanent.

Thank you, appreciated your input.
Sarge