If you have hard water, mineral deposits can accumulate in the rinse holes around the rim of the toilet, causing a weak flush. The fix is unusual, but simple and effective.
Use a hand mirror to see the holes under the rim of the toilet. Bend a coat hanger flat and probe the tip into the holes to poke out any mineral deposits.
If your toilet flushes slowly, the rinse holes under the rim may be clogged with mineral deposits. With a mirror and a coat hanger, you can clean out those clogged holes without ever getting your hands dirty. The photo says it all—look into the mirror to see if the holes are clogged. If they are, bend a coat hanger flat and probe the tip into the holes to poke out any mineral deposits.