i recently bought a cheap nikkor 135mm f3.5 AI lens and it seems to be in pretty good condition except for some dust inside the lens. There isn't much though, and most of it is too small to be noteworthy.. however there is a large spec that i would like to get rid of. I was planning to send it in and have it cleaned thoroughly, but after checking up on prices it just wont make sense to do it. I'm thinking i could probably do this myself though, with some help. I've never taken apart a lens before, so im not sure how the mechanics look inside it. Anyone have a link to some schematics? Will i be needing any special tools besides some small screwdrivers? And finally.. Is this a good idea to do yourself?