I have some Mitutoyo micrometers that are stored in the original boxes, some plastic, some wood.

A while ago I found the foam liner in the lid and under the tools starting to deteriorate and stick to the micrometer. Luckily, I caught it early enough that no real damage occurred and the minute rust was cleaned off with steel wool and WD40. After that I check all my other Mitutoyo storage boxes and found the foam starting to deteriorate in some but not others, so to avoid a costly outcome I remove the top and bottom layers of foam.

After googling this phenomenon, I found it happens and usually the outcome is permanently rusted/ruined tools

What to replace the foam with is the question, I thought maybe felt and found some wool felt and even Merino wool felt made here in NZ.

So I thought before I purchased anything I would do a search and ask the question, after searching I find comments to avoid wool felt and others saying it’s ok. I see Gerstner use a 100% acrylic felt with sizing to add stiffness. When looking for felt I find Wool, Wool blend, Acrylic and other blends then there is Baize which is different to felt………..talk about confused.

What would be best to line the Mitutoyo boxes with? Felt or Baize, wool or wool blend or synthetic?

I have attached a photo of a Moore & Wright set of micrometers, still new in the box which someone (I assume) has partially lined with felt

Thanks

Ian