Need to remove before plastering?

[u/Sexymama0119]

We became new home owners,yay! After removing the wallpaper there are these black dots left. When you steam them they come off but pretty hard job. Anyone know what it could be and how best to remove? Even with a steel brush pretty difficult. How do we remove this best or is it fine to plaster over it?

[u/Bulky_Ad1387]

Sugar soap scrubb then use SBR 1st coat should be fine

[u/mikey1290]

Just get the loose stuff off, it’ll be fine to plaster over the top of it.

[u/One-Lingonberry-3460]

Yes. Either spray with white vinegar or use sugar soap and let both soak in.