Damp mark on walls, best way to paint over?

oil based undercoat and the emulsionDamp mark on walls, best way to paint over?
Before you put the final coat of paint on, paint the damp area and the surrounding bits of wall with a specialist damp-proofing paint, and allow to dry for 24 hours. If you are in the UK, you can get it at B%26amp;Q.Damp mark on walls, best way to paint over?
Just use a Brush and Paint...


Then Wax on wax off with the brush full of paint

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