If your idle jets are dirty, they have to come out of there to be cleaned.
Any product that will take the varnish left by old gasoline from a carb, will strip the lubricating oil right off the cylinder walls - don't want to run your engine like that. Seafoam, OMC tuner, etc. are safe to run through the motor but they won't clean the carbs.
You don't say what motor you have, but all the outboard carbs I've ever seen, only the hi-speed jets are in the bowl. Whatever you fill the carbs with, doesn't reach the idle circuit.
Better to do it right - pull the carbs, disassemble, soak overnight, blow out the passages with compressed air (or aerosol carb cleaner), reassemble with new kits, reinstall, link & sync, adjust mixture screws (if equipped).
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"The metric system never really caught on in the states. Unless you count the increasing popularity of the nine millimeter bullet." -- d. barry