Take a look at my new rebar and wood bookcase! I am super excited about the way this turned out.
After stripping off the paint layers (part 1 of the DIY), I used a Dutch oil in Dark Walnut to stain and condition the wood. When I was rubbing on the oil, I noticed two circular rings in the wood on the bottom shelf that wouldn't take any stain. I bet gramps made those marks when he was painting this shelf for the first time and they left imprints in the wood. How cool.
The final step in my shelf makeover was sealing the wood with a paste finishing wax. You definitely want to do this part outside, or in a well ventilated area, the wax is a bit stinky, but the results are better than anthing you could paint on. It gives a nice, aged, natural finish to the wood, with no funky brush strokes, bumps or lumps that polyurethane with create.