Comm Olefin.. Clear chair mat was over that stain.. I thought it might be the petroleum oils they use to make those mats that seeped into the carpet.. But if that was true it should of covered the whole area of the mat........................................................

Tried de-sov-all solvent...rust remover.. I know it wasn't coffee stain but gave that a try... Stain didn't fade at all..........................................

I Never saw the clear floor mat.. Don't know what was on the bottom of the mat....

ANY THOUGHTS.... Maybe a patch job??????????

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I saw something that look very close to that stain and it was also a yellowish colour.

It was in an office where thay had a clear plastic mat ( the ones with little teeth underneith ) and it was the office chair that ate away at the plastic over time and the oil & grease from the chair wheels made a stain something simular to that pic.

I suggested a dark smoked plastic mat to cover the stain...........and it was business as usual

                               Nightrider

It's interesting to see that the pattern is almost exactly where the chair casters would roll - I think NR could be right however I have another theory.

The pressure from the wheels may have has caused a wicking from something under the carpet on the floor.   This looks like a job for PadMan.

What can padman do that anyone of us can't do?????

Any Stain super expert's out their????

I would clean with a olefin prespray boosted with a Citrus solvent and a powdered peroxide. Then pad it out with cotton pads. Then see if there is still transfer on the cotton pads. Take it from there.

Then consider citric acid.

That looks like a stain from down under...most likely before the desk mat was put there.... I find in a lot of commercial buildings the office gets moved around and most times before the carpet is layed the concrete isn't power washed.

Thats why I hate commercial to many mystery stains

Personally I hate commercial... so it could rock all it wants

John;

I highly doubt that that particular discoloration will come out--------------------------------------------------------- ------------------------------------------------------------ -------------------------------UNLESS----------------------- ------------------------------------------------------------ ------------------------

You CUT IT OUT !!!!

Good Fortune to you and solving this situation;

Ed Valentine

John

 First clean as you would normally then try acetic acid boosted with a small amount of citric acid (circa 6 - 9ml/pint)  the removal effect develops over the drying period.

 If that doesnt work as a last resort try sodium metabisulphite.