It depends on what you want, magnatec car oil (Castrol GTX Magnatec) will really make the bracelet smoothe to use, and push pins/screws will slide out much better. To use it I put the bracelet in a zip lock bag with the car oil, and leave in a cool dark area for 3 hours, then soak in soapy water, and rinse heavily.
If you want to refinish as well, then garage door lubricant is very penetrating, and gives a beautiful shine to the bracelet, looks very nice when done, same procedure as before.
I have used both, both with perfect results (my semaster bracelet had 2 screws that were burred, and wouldnt budge, 3 hours in magnatec and they came right off, and the bracelet felt nicer)