A completely vague question.
A toilet can be kept clean with a toilet brush or even with a toilet tablet that sits in a cradle and that you clip onto the side of the toilet pan, never put any kind of liquid or tablet into the cistern with the working parts of your toilet. its pain when doing maintainence and the chemicals can shorten the life of the plastic working parts
flush your head in the toilet
your toilet is working correctly,the reason it does this is because toilets flush by weight
clean it with used toilet paper
because the upstairs toilet drain was clogged up.
A working toilet
Partical stoppage. Bad Venting , Refill tube not working
People that cleaned a toilet for the people in China. They also bathed people if they were working for a very rich family.
A design of a toilet in which humans excreta is treated by earthworms has been tested in India. It has been found to be a novel, low water-use toilet for safe processing of human waste. The operationg of the toilet is very symple and hygienic. The human excreta is completely converted to vermi cakes - a resource much needed for soil.
My g/f has this happen to her regularly and, it was only when I asked that she said she usually flushes once to get the flush working and then immediately after to make certain the toilet flushes everything away. She said that if a toilet has good pressure, it will often splash out when she flushes.
If you have an old broken toilet and the sewer/septic system works you can pour a gallon or so of water in your existing toilet and it will flush. If you don't have a working sewer you can use a 5 gallon bucket for your toilet and dump it outside after use... very nasty. The EPA, and your neighbors won't really approve. Throw your old toilet seat on the bucket for added comfort. You can also dig a hole outside, use it and bury the waste.
If the toilet bowl fills lower than the previous waterline, the tank may not be working properly. Check that the float is moving freely and allowing the tank to refill all the way. Also make sure the filler tube is filling the toilet and is not directed elsewhere.