I seem to remember hearing an archaeologist on a radio program talk about runes on the inside of viking shields, animal names the likes of “bear” etc. but I can’t seem to find them - so I’ll settle for these example s of runes being inscripted on shield handles, albeit in silver or brons so they might have been ornamental shields for all I know:
The middle one is interpreted as a name “Svarta” - meaning Black. I’m more inclined to interpret it as “Sparta”. 