Cleaning HP41C keys



This is my first post to this esteemed forum. I've been lurking for a while just trying to get a feel for the place.

I have been a fan of HP calcs since I got an HP16C, I needed to develop a large chunk of C code to handle 18 bit signed arithmetic. I could not have done the work without that calculator and still have it.

Since then I've got an HP17BII, an HP20S, an HP12C, an HP15C an HP48GX, an HP41CV and a rather grubby HP41C. I may have missed one or two out now I think back on this.

Anyway, most of them are in excellent condition but I've just got my hands on an HP41C and need to clean it up. It's physically in great shape but the keys seem to have a thin layer of grease and dirt on them. It means when you use the keys, you fingers stick ever so slightly to them.

Does anybody have any suggestions they have actively used and can recommend? I could use pure alcohol and cotton buds but am wary of doing any damage to such an old gem.

My intention is to use the HP41C for work, we have close to £10M of comp hardware in my dept but a good calculator is hard to come by :)


I've had good results with

a) isopropyl alcohol and a Q-Tipp

b) immersing the whole keyboard in an ultra sonic cleanser at an optician's shop

c) tissues to clean plastic car dashboards


I use Windex on a Q tip to clean dirt off keys and keyboard, followed by another Q tip moistened slightly with water. I never like using alcohol when I'm cleaning plastics (unless I'm drinking it)


Thanks for the advice. Would never have thought of Windex.


Forget the cotton swabs, takes all day!

Windex, soft toothbrush. Wet lightly, scrub. Wipe with soft towel, blast with canned air to remove liquid that accumulates around keys, wipe again, blast again. Repeat if needed. If it is really dirty, allow the windex to soak while holding calculator upside down so it does not run willy-nilly into the keys.

This method is okay on the 41 *only*. Classics and others may not hold up to brushing. The construction of the 41 is quite different and is the most tolerant of aggressive cleaning.

Edited: 11 Sept 2011, 10:10 a.m.

Possibly Related Threads…
Thread Author Replies Views Last Post
  Cleaning old slide rules aurelio 3 1,901 09-18-2013, 03:25 PM
Last Post: aurelio
  Cleaning exiting library programs patryk 2 1,311 09-14-2013, 12:36 PM
Last Post: patryk
  How to check / repair a HP 82106A module for HP41C calculator ? Eduardo Mingo 13 4,372 01-07-2013, 11:05 AM
Last Post: Diego Diaz
  A simple question about the HP41C or HP41CV Antoine M. Couëtte 6 2,374 12-16-2012, 04:06 AM
Last Post: Antoine M. Couëtte
  HP41C repair ? Michael Paul 4 1,802 09-30-2012, 11:26 AM
Last Post: db (martinez, ca.)
  A cheap HP41C for sale...........999 EURO only aurelio 4 1,917 06-04-2012, 03:46 PM
Last Post: jerome ibanes
  HP41C: Factorial (kind of) in MCODE Frido Bohn 7 2,453 05-26-2012, 09:18 AM
Last Post: Frido Bohn
  Woodstock/Spice Keyboard Cleaning Revisited Matt Agajanian 0 1,035 05-12-2012, 03:43 PM
Last Post: Matt Agajanian
  Picture of HP41C from "The Dream is Alive" Christopher Johnson 0 1,097 04-20-2012, 02:38 PM
Last Post: Christopher Johnson
  HP41 Cleaning Advice John Abbott (S. Africa) 5 1,904 04-10-2012, 01:51 AM
Last Post: John Abbott (S. Africa)

Forum Jump: