Alternative case for the HP-41

[rprosperi]

(01-29-2020 07:41 PM)Massimo Gnerucci Wrote:  

(01-29-2020 06:34 PM)Jurgen Keller Wrote:  The powdery residue comes from the black lining inside the case. Put the cases into the washing machine and choose a "soft" program. You may even turn the inside out to get better results. That usually solves the problem.

Yes, that's how to solve this problem.

1 +

An alternate and easier procedure, if you have access to an air compressor with a trigger nozzle, is to just blow it around inside, holding the case upside-down (so the junk falls out). The high pressure stream has enough impact that it definitely loosens all the disintegrated lining stuck along the walls.

Using either method, you may have to repeat the procedure every 6-8 years.