if the toilet flushes solids well with a bucket.

by a gallon of muriatic acid, safety glasses and a funnel one that
will fit in the dip tube top opening.

put on safety glasses, open window, it will smell bad.

put funnel in dip tube, take deep breathe, pour a quart or so in
funnel, avoid splashing,,,,,leave room. shut door.

20 minutes later flush toilet 10 times minimum. to clean out the acid.

this will clean the bowl rim passages, the passage at the bottom, and
all the interior passages inside the toilet.

you can drain toliet bowl if you want but thats not really necessary.

the acid dissolves hard water sediment in the lines and openings.

total cost 1/2 hour and under 10 bucks