tl;dr: Ultrasonic cleaning works wonders for Alps switches, making them feel new again. A tiny amount of Teflon oil makes them even better!
Alps key switches tend to suffer more than most when exposed to dirt, dust, and other contaminants. Dirt enters the switches easily through the tops. Due to close tolerances the dirt interferes with travel resulting in a scratchy, gritty, slow, mushy, or grinding feeling when keys are pressed. This is all too familiar to anyone with an old Alps board.
We had discussed ultrasonic cleaning in some other threads, most recently
https://deskthority.net/photos-f62/ultrasound-keycap-cleaning-t14413.html. The ultrasonic cleaner should be perfect for Alps switches with all their small hard to access spaces. There was some concern that the cavitation could harm the click leaves and switch plate leaves. Some research suggested that a fairly neutral pH should not damage thin metal parts in the sonic cleaner.
I experimented today with cleaning some Alps switches. The configuration was as follows:
Alps SKCM White and Cream Damped switches
iSonic P4820 ultrasonic cleaner
Solution consisting of two Efferdent denture tabs, about 1.5 tsp 7th Generation dishwasher fluid, and reverse osmosis water at about 60 C
Disassemble switches
Clean for 480 seconds
Remove, rinse in distilled water, dry, and assemble
Here is a photo of the disassembled switches:
Switches disassembled. Switch plates remain in lower housing. Upper housing, click leaf, slider, and spring are separate.Here are detail photos of the click leaf and the switch plate post cleaning showing no visible damage.
Switch plate detail post cleaning.Tactile leaf detail post cleaning.Here is a photo of the switch about to go back together.
Assembly post sonication.The switch feels brand new. I cannot detect really any grittiness or hesitation. Some switches still hesitate a tiny bit in response to aggressive off center key presses. There is a small chance that enough abrasion over time roughens the plastics themselves.
I did experiment with lubrication using a tiny amount of Super Lube 51010 synthetic oil with Teflon. I applied a tiny amount, as thin as possible, with a toothpick all over the slider. This improved key feel even further.
I'm looking forward to applying this technique to all the switches on a very gritty Northgate Omnikey 101 to get it back into working condition.