I make reproduction medieval leather-frame spectacles for historical reenactment.
This pair I forgot one step and permanently marked one of the lenses
Step 1: How Not to Make Leather Framed Spectacles
I cut out the leather frames and get the lenses from an online company.I take the lenses out of the commercial frames. I make sure the lenses maintain the same orientation and put them in the leather frames. Then I heat them and seal the leather with beeswax.
I usually use a sharpie to put an L and an R in the middle of the lenses to make sure the orientation is correct. I usually wipe the lenses off before I bake them. This time, I forgot and baked the sharpie marks onto the plastic lenses.
I tried hairspray, WD40, but no luck. I could lighten the marks but they were still very obvious. Luckily, a new set of lenses was only $10.