Joined: Aug 2009
Posts: 7,703
Likes: 4,021
From: Berkeley, CA
Bikes: 72 Cilo Pacer, 72 Gitane GT, 72 Peugeot PX10, 73 Speedwell Ti,l, 75 Peugeot PR-10L, 80 Colnago Super, 81 Zinn, 85 ALAN Cross, 85 De Rosa Pro, 86 Look 753, 86 Look KG86, 89 Parkpre Team, 90 Parkpre Team MTB, 90 Merlin
I don’t know if it’s scientifically sound, but I’ve found rubbing on a small dab of vasoline with a rag will bring back the luster of Delrin. I started doing this a few years ago and my Delrin bits have remained deep black with no cracking or other ill effects.