Take it to the machine shop. Especially if it has been disassembled for some time. Bugs and other crap loves engine blocks. They think they are a condo or something. Mainly, mostly, and not to mention very importantly, is the oil galleries which is kind of tough to get even with a good pressure washer.
If you have just recently disassembled it and bore taper, cam bearings, etc looks alright. Yeah you can use a good chemical like mineral spirits (cheap), and other asorted cleaners.
But I still recommend taking it to a machine shop. Just call around and ask what they will charge to do it anyhow.