IMO home painting is rarely worth it. Whatever you can apply will be much softer than the factory paint and a lot more prone to chipping and scratching. These days, scouring the surface, a good clean and then Hammerite applied with a brush is what I do if I think I have to. If ever I'll want a better result I'll drop the bike off to be sandblasted and then Powdercoated.
But there are several ways to get a bike back to bare metal. Some start by scraping them down with an industrial razor blade. Some use a steel brush wheel in an angle grinder. Some go the chemical route.
Pick method according to frame material. Can't do wire brush on aluminium for instance.