I've NEVER been able to get a single one done right. I just remake the print. I'm fastidious enough that I usually don't have dust but... when I do, all I've ever been able to do is get a darker ring around the spot. The spot pens are the worst in this regard. All they've ever done for me is make the spot look worse. I thought it was because they didn't work well on RC paper until I went to FB and found that works no better.

I think this is something I'd just have to have personal instruction in and watch someone do. I've been trying off and on (between just giving up and re-making my prints, and of course not for the decade off from photography) since the late 70s and if I haven't managed it yet...

It's impossible. Some people only manage because they don't realize it's impossible, so they manage to succeed.