I went back and read that. I'm not saying oxygen is the cause of the problem. I'm just saying the snot remaining on the stem will block its access to oxygen and cause rot.
You may have to rinse them more than once if it comes back. Perhaps you could fix the labeling so that you don't mix them up. Maybe just take a picture so you know where each one is while it's labeled currently.
Personally, I just use tap water, maybe slightly chlorinated if you'd like. I've had cuttings root even with snot on them. Just have to keep an eye on them so they don't get rot due to lack of oxygen.
I think the cure would be rinse off cuttings. Clean tank and aerator very well with cleaning solution like hydrogen, peroxide or bleach. Then refill with clean water and make sure you refresh the water More often.
When it dries it's going to leave a small film of soap and diatomaceous earth all over everything. The leaves should be stained with powder. Aphids do not like it.