Two things...just communicate condition issues always and don't assume a card is unwanted because of its condition. I'd also not spend time adding condition to all cards, but I will mention any issue with cards that are requested. Scans work well, but even then an explanation may be needed. Always be upfront with that information and you'll be surprised with some responses.
I accept lesser condition cards, even newer ones as I'm more concerned with finishing a collection. If I wish to upgrade later I will, but I don't recall ever doing that. But bottom line is I wish to be informed of condition issues when one is offered.
“Aslan didn't tell Pole what would happen. He only told her what to do. That fellow will be the death of us once he's up, I shouldn't wonder. But that doesn't let us off following the signs.” - Puddleglum in The Silver Chair by C. S. Lewis