Sealing Old plaster - Zinsser BIN or Mist?

Hi,

I have stripped back wallpaper to bare original plaster and whilst generally it's good there are a few small patches of what I think is old PVA or wallpaper backing residue left.

I'm aiming to paint over in white. I will try to get any remaining residue off but then was thinking do I:

Use a sealer like Zinsser BIN (I have a grease spot in the kitchen so have a tin anway)
Or Mist at 70/30 White matt say 2 times

Wall is likely to be skim plastered again next year professionally if it makes any difference. Today is just to get it looking half OK.

Cheers

As you've got the zinsser you might as well use it on the grease and small patches - then just one mist will be fine.

Thanks Nige, this particular wall (well it's a on 2 small sections doesn't really have any stains (the one in the kitchen does). I'm assuming that the zinsser is ok on totally raw but old plaster (I'm assuming the zinsser won't peel off like a normal paint might if not misted?)

Might be better with Zinsser Gardz.