[Doing the following may break your equipment and/or void your warranty. I'm just sharing info that worked for me. Proceed at your own risk]
So I took my out-of-warranty GoTo mount (Orion 7817 GoTo Upgrade Kit for SkyView Pro EQ Telescope Mounts), which runs on an Astrozap EQ mount, and the ESC and MENU buttons wouldn't function. The buttons generally had been getting wonky, so I figured it was time to clean the hand set.
I removed the 8 screws on the back, opened it up, removed 4 more screws inside. All are small Philips head. I did NOT separate the ribbon cable connecting to the LCD screen, and was very careful not to tug or mess with it. I carefully lifted the circuit board and rubbed 50% isopropyl alcohol on the golden contacts. I then removed the rubbery keypad (like a TV remote) and rinsed under water and washed with mild soap. You will see 2 black raised dots (I assume some kind of ferrite?) on the back of the keypad that touch the circuit board. I washed these as best I could.
Then let dry throughly. There can be water hidden in the rubber membrane so don't take any chances.
When dry reassemble the handset. All buttons seem to work as good as new.
YMMV. I'd appreciate any tips in case I did this wrong.