it is something underneath causing a stain, right? where i have had similar I have used something like Zinser primer. If it is some form of oily or greasy substance, it might take a couple of coats.
@tmevans started
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it is something underneath causing a stain, right? where i have had similar I have used something like Zinser primer. If it is some form of oily or greasy substance, it might take a couple of coats.