In article , Janet Baraclough.
.. writes

LOL. For anything I hope will be a permanent fixture, like azaleas or
clematis, I use a thin but indestructible copper label (sold by Lakeland
Plastics) indented by a biro. Anything else like seeds or cuttings gets
a plastic label and pencil. Pencil lasts far longer than "indelible"
marker pens ime.

However, I'm so mean and idle I use each plastic label four times
(both sides, both ends) before cleaning them off with a brillo pad and
starting again.

I find spit and a firm rub with a finger works perfectly well.

--
Kay
"Do not insult the crocodile until you have crossed the river"