ebay is probably your best bet. You will find that not all parts are in equal demand.
A sale as a complete unit does not leave you with odds and ends for which there is little demand. Parting out is a gamble that enough items will sell and high enough
price to justify time and effort. As you have found, rust, corrosion and crud can
make some disasembly risky. Some fasteners on some motor are notorious for snapping
off and being VERY difficult to repair.
All the above is water over the dam. ebay is an auction...supply and demand drive the
bidding...results will vary...depends upon how many need what you have to offer and what
they are able and willing to pay.
Clear photos, accurate description and response to questions may help give potential
bidders confidence in you and your merchandise.