I used to scavenge a lot in a similar manner.
I found for motors old printers were the way to go, but to be honest with the trouble of getting it all working... after the trauma of trawling for datasheets etc, I now find that ebay with the cheap Chinese parts is the way to go for me.
Most of the parts I took out were good for nothing more than the de-soldering practice.
Unless you have the time, it is often easier to buy parts to spec than to make do... although, I'm guilty of making stuff work "just because I can" - and in fact am waiting for a moment to feel brave enough to start trying with an imager ic I took out of an old scanner (and *did* find a datasheet for).
pudn.com, baidu.com are your friends. and anything in chinese in general, thank god for the "openness" of the chinese electronics community. get clever with finding products in a similar family.
Now there is something I never thought of.... thanks for that tip, Ill try it next time I get stuck.