Only dealing with stained glass sheets right now - old eyeliner pencils 🙂 they stay on better than a tile marker, ask your wife or girlfriend if she has some old ones lying about and try it.
yep, even lipstick has its place - I don't like wearing it so don't mind sacrificing some age old lippy :lol: really handy when you need a bright mark :lol:
Another really good thing I discovered lately, if I have a really complicated shape on stained glass, I draw or trace the shape with marker pen onto some tracing paper (greaseproof paper will do), spread copydex on the back of it, glue it down on the tile and use my very wet ringsaw, what a beauty that is 🙂 the saw cuts no problem along my marker lines, the paper and copydex can cope with the wet, and the copydex just pulls off easily afterwards, the glass is unmarked, an absolute doddle if you have a complicated shape