I've just had to sort a squeak on my Helix LT pedal. I followed the following video by Chuck Brand https://www.youtube.com/watch?v=_2TgtCzZHng which addressed the concerns I had about opening up the helix LT, and the process was pretty simple. Now he doesn't touch any of the circuit boards, but you can clearly see how it all hangs together once the case is off.
However, the inside was pretty clean, and I've had the Helix on the floor and uncovered for 2-3 years, albeit in a cat/dog free house.