The side with the sealer was green/3 months new when I applied it. I got the sealer in a 5gal bucket at an industrial supply house that sells to contractors. To recoat this side with the epoxy, I'd have to abrasive sand the whole thing then acid etch, something that I'm not looking forward to doing. But the biggest part is cleaning everything out of the garage for 72 hours while the epoxy sets and hardens.
I bought the $30 epoxy kit (from Sear's) for my new addition anyways, not the old floor. The crete was poured in October so not much, if any, cleaning to do. Either way, the kits come with a wash and etcher and are marketed for home garages not necessarily new construction. If you follow the instructions in the kit, you'll get good results. I doubt if I'll put down the contrasting color chips that come with it buy maybe? The main reson for the epoxy is to keep it cleaner while I work, but also for the look.
I'll post pics once it's done. Gonna be a while.