Find My Markers

I need to find my property markers to decide where (if) I want to install a shed. I’d rather find them myself before paying someone. I know my husband and I found them like 20 years ago. Seems like the back 2 were rebar with pvp pipe sticking out of the ground. One side says it’s CM. The one I’m most concerned with right now is my front corner and it is marked IR. I remember saying something to the effect of “ok so we know it’s by the phone pole.” But now I can’t remember if I actually found it or was making an assumption. The survey does not show utilities. I’m also on a flag lot, so that makes it a bit more difficult. I do have a metal detector. Any advice as to how to find it? Would they ever be next to a phone pole?