For polishing fine scratches out of precious resin, Wenol has proved its worth; Montblanc itself uses and recommends this polish, and a tube lasts more or less for ever. For parts made of acrylic, Displex is a useful addition. Special precious-resin polishing wadding from the accessory trade also gives good results — a scratched Meisterstück ballpoint can be brought back to something close to new appearance with it. Expensive unbranded polishes, such as those sold by mail order for around 16 euros (as at 2011), offer no discernible advantage over the established products.
Deeper damage is another matter: cracks and engraved dedications cannot be polished out. The obvious idea of filling them with a two-part synthetic resin from a craft shop, shaping it with fine abrasive paper once it has cured and then polishing it, is conceivable in theory but is not established practice among collectors, and there are no reliable accounts of it. The real difficulty lies less in the filling than in matching the colour of the resin exactly to the aged precious resin. For damage of this kind the route normally leads to a specialist workshop or — with Montblanc — to the manufacturer itself.