Obviously Simple Green is an oxymoron.

When I bring an old bike home with hints of deferred maintenance, I spritz all the bolts, nuts that have to be removed with a rust penetrant. Then I stow away the bike until I am ready to work on it.

If the bike frame or driveline components have grease I spritz them with Home Depot HDX degreaser. It's not better or than anything else, but it is cheap and appears to work well enough. If it is caked on grease from chain lube, a spritz of WD40 goes on before hand and is allowed to soak in. The parts go into a Harbor Freight Ultrasonic washer, the frame is often just wiped with a damp paper towel or scrubbed with Dawn and a dish brush.

After final reassembly, the frame is cleaned again and I spritz with spray Turtle Wax.