HP-41C: The "1" key fails sometimes (weak contact).

[Dave Britten]

Cleaning the key contact with a little Deoxit is no sweat - I've done it plenty of times myself, with great results. HOWEVER, the main risks in opening a 41 are cracking the screw posts (a few of which I've also had to repair), or dislodging/damaging the zebra connectors (had to clean the connectors pretty aggressively to get my 41CV working again after I opened it, but it's fine now).