I've just had my 1990 +8 badge restored by a colleague who restores antique enamel work. He did it with 'cold enamel' and it looks really good. I see that replacement badges are fairly cheap and I don't know if the quality has improved. Mine is not solid, just pressed thin sheet (brass?) and the black surround flaked off years ago.
If I can work out an alternative to Photobucket I'll post some before and after photos.
1990 +8 Connaught Green
1970 Lotus Elan S4 SE
2006 Aston Martin V8 Vantage
1973 Lotus Europa TC/Special