The water inlet CM is talking about enters the bowl at the front below the waterline. You can check for entrained 'stuff' by gripping the small angle of an allen wrench and scraping around inside the inlet (which is about finger sized) with the longer shank. I think CM is right and that's the only place such 'residue' can be trapped from the earlier plunge-a-thon. If the allen wrench comes up poo, you might shut off the water valve and flush the reservoir so the tanl is empty. Then holding the plastic/rubber/synthetic parts of the flush mechanism out of harms way pour a little liquid plumber or similar down the flow outlet from the tank and let sit for 15 to 30, then open water valve and refill tank and flush a couple of times to see if you have loosened things up in the 'bowels' of the flush mechanism. Be careful to not get drain cleaner of the flush mechanisms parts as the cleaner usually contains sodium hydroxide (strong base) and could damage their ability to seal