older home, and plaster walls question- fixing nicks etc..

[KOS]

I have finally removed several layers of wall paper in a home around 50 years old. These walls are plaster, nice and thick.

Apparently there was some damage time ago and the prev home owner repaired areas with sheetrock.. They patched areas. After removing the wall paper I can see the seams from the sheetrock and the walls are uneven with the plaster. In other words I have some areas that are 3 by

3 that have been patched with sheetrock, the rest remain plaster. I want to paint these walls. Instead of skimcoating, which would be quite costly, I am patching the areas of and will then sand. I have been using wall board joint compound. Tool wise, what is the best tool to apply this? I have been using one of those flexible spatulas.. any advice one can offer on how to save these walls? Do not want to wall paper

[wildo]

use a bonding agent on the old plastered sections of wall otherwise the joint compound will not stick. also I would recommend using a wide mesh (3 ft) on the wall (after bonding agent) to tighten up the old plaster and sheetrock seams.