That's why they advertise some stands and hangers as 'nitro safe'. Anyway, you can also use that foam tubing used for plumbing insulation. Not the black neoprene (wetsuit material) stuff, it's grey and sort of semi-rigid. It's not too attractive, but it works, and AFAIK, it's safe for the finish. Of course, I don't have any expensive, nitro ... More @Wikipedia
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