i just bought myself a new guitar, it's a kasuga scorpion...
http://brochures.yokochou.com/guitar-and-amp/kasuga/198x/en_index.html (first picture)
Now it's pretty good, but when i play it in distortion the pick-ups are very noisy, is this because of the thirty years of dust and dirt that they have endured and can this be cleaned? The stock pick-ups are, i think so, dimarzio's so that's pretty good...
so is it worht trying to clean these ones or should i put some new ones in?

My Gear:
Simon&Patrick Pro flame maple (so nice)
Epiphone SG-special (cherry red)
Richwood acoustic
Lany 30 Watt amp, not sure what exact model
they're probably noisy for two reasons:
1) the pickups have become microphonic
2) old wiring with poor shielding.

The reason they become that way under distortion is because distortion magnifies all the little quirky noises guitars have. These are pretty easy fixes, and can be done yourself. You'll have to repot the pickups, you just need a crock pot, some tie wire/coathangers/anything mcgyver-ish like that, and some paraffin wax and beeswax. There's a lot of good articles on this so I wont get into it.
To help with shielding, pick up a roll of conductive adhesive-backed copper tape, and line the electronics cavity with it.
Good luck