I just use compressed air to blow off the sawdust and a clean rag to finish the job. NEVER, NEVER use carb spray in a 2 stroke carb on any 2 stroke engine. Carb spray is very dry and will immediately strip the oil off the piston, rings and cylinder walls and cause scoring. If the carb is questionably dirty, remove it, strip it, soak the body and parts in a solution like Berryman's B12 Chem Tool, rinse it in water, blow dry it and replace the diaphragm with a new one or buy a rebuild kit. Cotton swabs are great for getting coagulated crud out of nooks and crannies too.