Is there any best way to remove sail numbers and the left over glue from a secondhand sail.
fingernails and an orange based goo remover, I've even had success with a small pump pack orange based room deodorizer from the supermarket.
or eucalyptus oil to remove glue, then wash off very well with warmy soapy water and rinse really good (you don't want anything left that could harm the mono)
My all time favorite for removing texta sail numbers is brake fluid. Yeah I know it sounds bad, but it seems to work well and as far as I know doesn't hurt the monofilm.
Its probably no good for stickers though, but I thought I'd mention it anyway 
