I bought this pen in Munich a couple decades ago - my daily drivers back then were Pelikans so this one never even got inked... I was collecting at the time and now that I'm pulling pens out for the first time in forever I'm finding some of them need polishing. Should I take this to a Montblanc boutique and have them clean it or is there a product I can use at home to address the filigree without risking damage to the resin?