Yellow patch appearing on pine floor

Q: In our bathroom we have 30 year old pine floorboards that had previously been stained and varnished. I stripped the varnish off and sanded to reveal a nice distressed look. Then I used Sadolins floor oil. The result was very good. However, a month later I have a yellow patch appearing (about 8 by 8) and I can’t get rid of it. I’ve tried sanding, but the yellow only seems to get brighter.

Do you have any idea what caused it and how to remove it? I don’t want to replace the planks.

A: It sounds like something was spilled on the spot and has either reacted with this oil finish or soaked past it and discoloured the wood itself. I would suggest contacting the finish manufacturer to see if they have any suggestions.