Brown stains on vinyl

[Observer]

The white vinyl upholstery in the cockpit has recently developed patches of brown stains. The only possible cause I can see is a sunscreen oil (P20 which we sometimes use on the children) and the positioning of the stains is consistent with that. I have tried several conventional methods of removing the stains (detergent, bleach solution etc) without success.

Can anybody suggest other ideas for removal and/or confirm the cause?



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