I grew up in an old house and my father always told me to use joint compound and tape (if needed) to repair lath & plaster, so it's what I've always used. I had a large area where the plaster was broken away and I just built it up in thin layers using joint compound. Thinner layers (drying between each layer) is better because it dries evenly and avoids cracking. Apply the mud neatly, then instead of sanding, use a slightly damp sponge to smooth the finish after it's dry.

thanks for the advice--looks like that might have less odor than vinyl spackle, which I appreciate. Anyone have input on the safety issue? If I am not sanding--smoothing would be sufficient given the rest of the wall's appearance--could I skip the mask? I do not play around with safety, but as I understand it the risk is in the dust, not fumes.

You just need a dust mask, not an N95.

Joint compound is the way to go. They have low-dust formulas if the dust bothers you. It isn't dust-free but it's less than the regular stuff.

I also prefer the kind that you mix the powder with water, because it doesn't shrink and it sets a lot quicker so you can do multiple coats in one day. You can get stuff that sets in 20 minutes but I personally think that's too fast. I'm not that quick! I think I usually get the 90 minute stuff.

It's a chemical reaction that causes it to cure as opposed to the premixed stuff that needs to actually dry to become hard.

thanks, once I get it done I'll report back.