Put on your gloves, and prepare your mind. In order to detect signs of clogged jet holes, you need to place a small pocket mirror underneath the toilet bowl rim. Take a closer look, and try to get an idea about the cause of clogging.
Now, insert a thin but strong wire into the clogged jet hole, and try to scrape out the debris. Make sure you don’t scratch the bowl.
Clear all the jet holes under the bowl rim by repeating the same procedure as many times as required.
Also use the wire in the siphon jet hole that is located at the bottom of the bowl. Again, you need be very gentle, making sure you don’t damage the bowl.
Use a brush to remove any remaining deposits under the rim and near the siphon jet hole. You can be a bit vigorous at this stage.
After you are done with the scrubbing, flush the toilet and see whether the water flow is normal. This procedure must solve your problem, if the clogging is not too big.
If you are facing heavy mineral deposit build-up, you need to go a few steps ahead. Dry the bowl and rim by removing the water with the help of a plastic cup. Make sure you pour a bucket of clean water before starting the procedure.
Close the holes by placing duct tape. Pour a half-gallon of vinegar, and allow it to stay in the channels for at least half an hour. Now, scrub with the wire, and flush the toilet time and again.