I just used the Wal Mart blue can carb cleaner on a Toro foam air filter it expanded by 20% also expanded a carb float bowl gasket on Tecu by 10 %. Do not use the cheap stuff buy Gumout or Berrymans at Wally world. Any one know if it expands the carb seat in a Toro GTS lanmower 2 stroke now float will not drop.

any type of carb cleaner will destroy a foam air filter

I've tried several carb spray cleaners and have found the Wal-Mart blue can to be the best for the money. Carb spray cleaners are NOT to be used for non-metallic parts, e.g. foam pre-cleaners are to be washed in warm soapy water, then thoroughly rinsed and dried. Then soak in motor oil and, using paper towels, remove as much oil as you possibly can.
Carb spray cleaners, and compressed air, are to be used to clean out all the carb's tiny fuel and air passages/orifices.
If the carb is so dirty you have to soak in a carb dip for an hour or so, it's best to put in a replaceable inlet needle seat, if it has one, as well as a new inlet needle. You'll have much higher success rate.
hope this helps.
thanks.