Old primed walls are now stained and oily

Question

I discovered the walls going down to the basement were only primed and never painted. Looks like one coat also, I doubt if it was more as several parts have been torn and it looks too thin of a layer. Down the railing is a lot of oily residue from lotions and other things on peoples hands and lots other marks and debris.

How can we save this drywall? What's the cheapest way around this issue without putting up new drywall? I worry that the oil residue especially will not adhere to the paint.

EDIT: This is not related to the "duplicate question" of preparing walls for repainting because these walls have never been painted in the first place, they were only primed years and years ago and thus have been completely ruined. This is a question about restoring the old primed walls not repainting.

Answer 1

Try to gently clean the oily areas with TSP and water solution. Use a sponge, don't scrub, but gently wipe to prevent damaging the area. This should neutralize the oily spots.

Where the drywall facing (paper) has been torn, I have had good results applying a thin coat of latex caulk spread and smoothed out with a drywall knife.

Then prime with a sealer primer. and you are ready to paint.