2001 Chevy suburban rough idle

Hello, I own a 2001 Suburban (68k miles) and it runs realy rough at idle. I brought it in to the dealership last lear for the same thing ,and they  cleaned the throttle boby and all was good. Now 10 months later the same thing, Im just curious to see if anyone has any experience with the cleaning of a throttle body and if this is something that can be done in the home garage. Yep Im cheep and looking to save my self $85 bucks. Any help would be greatly appreciated. Thanks