I must admit I did for quite along time. As of the last few years I haven't since my parts are overtaking the room in the garage. It was alot of fun, hoping to find decent aluminim components and what not. I have been able to salvage several bikes and turn a small profit from them.
My best find was a Gitane Tour de France tossed out by none other than my neighbor across the street!!!! She didn't have a clue to it's worth and handcrafting. I did inform her that is was a very worthy vintage bike from France but she said to take it anyways. I cleaned it up and rode it for a bit then sold it!
Presently, I am s-l-o-w-l-y building a hybrid out of a woman's Gitane mixtie frame for the wife. Found that in the trash too.... the frame not the wife!