At first I thought you meant this kind.
But when I did a search I found sea foam motor treatment and this:
I didn't know there was such a thing
Yep, I use it all the time. Just restored an old MG and it does wonders for clearing the junk out of old carbs. Comes in bottles and sprays and can be poured or sprayed (slowly!) directly into the carb throat, but use it outside; you’ll get black smoke until the carbon and other deposits are removed.