You can polish the black off. I don't know if it'd work very well though - even when melted it'd be very viscous and if it caught fire it'd possibly leave a nasty residue.
If you've got the other dust cap off, see what dissolves that. Acetone aka nail varnish remover might well do it. If not, try cellulose thinners (from motor factors).
You can polish the black off. I don't know if it'd work very well though - even when melted it'd be very viscous and if it caught fire it'd possibly leave a nasty residue.
If you've got the other dust cap off, see what dissolves that. Acetone aka nail varnish remover might well do it. If not, try cellulose thinners (from motor factors).