I have a small issue. Few months ago my apartment got renovated, and I listed all holes in walls i want to keep for future use. The rest was, depending on depth, filled with concrete or plastered. And it was done really good, I can't see these spots with my bare eyes.
Now, I forgot to list one hole, so it was plastered clean. But I need to have a hook there, and I'm reluctant to create brand new holes. I would really prefer to use existing one - I need bigger diameter now, so I can afford to be a tiny bit off, but boring new hole would needlessly affect concrete, and if it happened to be just next to original one, it would also be weak. So one way or another, I need to find old one, be it to reuse it or avoid it. But how?