So of course, the boxes i find are swap meet finds or a few online purchases. Most, if not all, are pretty dirty. Aside from the dust, there seems to be the hard to reach places that need a bit of cleaning.

Is there a special solution or a certain these boxes should be cleaned? Any help?

There are loads of threads on the forum about this.  Everyone does it differently from a wipe down with a duster to a full strip down and bubble bath

I love a really really clean machine so I go full bath every time if possible, after stripping all the electronics etc first of course.  Just don't use anything abrasive or with solvents.

Have a browse of the forum you'll find loads of tips

Well the boxes i picked up recently are acutally in pretty good shape, i opened them up and seemed very clean inside. They just have a little dust build up here and there. i used windex on a old white t shirt on a hitachi and it didnt seem to hurt it, but i have heard it isnt such a great idea.