Wenol is well suited for writing instruments made of older celluloid, e.g. for classic 3-series models like the 342, but it should not be used on precious resin (Resin); there Xerapol or Displex deliver better results. On the 144 in precious resin Displex is unproblematic, on the celluloid 342 it is to be avoided since the material can swell strongly. Every polish removes substance from the surface and can additionally damage gold plating, which is why rings and clips should be covered with adhesive tape before polishing and frequent polishing should generally be avoided. Collectors point out that even Wenol can wear off gold plating with too much pressure, so one should always work sparingly and selectively.