What is the best cleaning agent? or what should I use to clean all the coils, terminals, etc? Thanks

Thanks for comments. I guess since it is so old I want to minimize issues before the first plug in so looking for advice (clean connectors, etc, etc). It is hieroglyphics to me when I open it up and I am not versed in electronics or electricity so have to walk through it slow. Appreciate those that have given comments and any future comments.

Quick question. The guy I bought it from restored many machines and he said I could "fry" some components if I was not careful to clean before plugging in??

I bought an old Bally Wild Wheels pinball machine from a guy who restored pinball machines. He said he always cleaned all the terminals and connections before ever plugging in. I bought it before he cleaned it...so it has not been plugged in. I want to clean and restore before I plug in. Any help in doing my own restoring, instructions, manuals, etc to get it running would be appreciated. I do not want to plug it in until I feel it is ready to plug in. Thoughts?