To clean - or not to clean ... ?

[HP67]

I am squeamish so I clean any used item I buy very thoroughly. I can recommend the Simple Green brand cleaner for external cleaning.

I am very impressed with this chemical. I buy it in concentrate and dilute it around 1:10 in a spray bottle.

What is impressive to me is that it cleans thoroughly, and yet it does not remove labeling, markings etc.

I had some amazing luck with a local product cleaning HP 48s. It was also germicidal. But I don't have it here. I used Simple Green on several HP 41 models with no damage.