I use simple green aircraft cleaner. Doesn’t eat aluminum and cuts grease and stuff. As for size I would recommend the largest you can afford. Go through Amazon or Ebay, as both sites have them cheaper than harbor freight (GASP). Go with the biggest size you can afford. Don’t be afraid to get one of the cheaper smaller ones, as having one with clean solution is great for carbs. Mine and the style I’d recommend are the stainless ones that look like heated food stations. I’ve had mine die on me once. The wires tend to be aluminum from the factory and some of the connections to the board are... flimsy. Soldered some good copper wire in where need be and haven’t had a problem since, knock on wood! All the parts are generic Chinese components so if anythjng ever breaks/melts you can easily repair the machine as well if you’re willing to take it apart!