"Although electronically, HP Pavilions are pretty
conventional for their time, they have rather unique case designs
with extensive plastic coverings. These were, as I mentioned, very
dirty.
"However, with care, it is possible to remove them (they are
attached with “one-way” plastic tabs that have to be
carefully pried and pushed through the openings in reverse. I
removed all of these plastic elements (except the base, which
wasn’t too bad anyway).
"Then, I carefully laid them out on the racks in a regular
portable dishwasher (yes, the same one we use for our dishes). You
can wash them on a low-heat cycle, just like any “top rack
safe” dishes. This is very effective at getting off old oily
sticker residue and other kinds of dirt accumulation. You do have
to make sure that they are thoroughly dry before attempting to
reinstall them"