4th topic, how to raise a clay pot?
Very first step is to season a pot. Clay pots were fired at lower temperature usually remain an earthy smell. Seasoning a pot is to rid of earthy smell. Brush new pot with clean toothbrush under water. Submerge cleaned tea pot in a large clean (oil free, odor free) cooking pot filled with purified water, bring it to boil and "cook" for 30 min, rinse hot teapot under cold water. For good quality clay pot, it should be good to start brewing tea. If clay smell persist, repeat boiling and cold water rinse a couple more times, add tea leaves to boiling water during last boil, let teapot steep in tea over night, rinse in the morning before brewing tea.
Step 2, find a suitable tea for the pot. In order to find out what tea can be enhanced by a clay pot, it's best to compare flavors of the same tea with same quantity, water, temperature and timing in a gaiwan and clay pot side by side. Gaiwan brings out the true flavor of a tea, both good and the bad. By comparison, if tea brewed from a clay pot taste better than gaiwan, then it is meant to be a pair. In most cases, it takes a few hit and miss to pair up a pot. Brewing a few different teas in the same pot will not intermix flavors of the subsequent tea while it's new. Raising a pot takes time and attention. If you do worry about that, just re-season the pot again by boiling then rinsing in cold water, repeat until you can't smell any flavor.
After you decide what tea to brew with a clay pot, the lengthy process of raising a clay pot will begin. I posted a short version of how to raise a clay pot here.
External raise can be done with various methods: polish with cotton cloth after pouring tea over exterior, or brush with tea then polish/dry with cotton cloth after each use, or rub with bare hand and tea then polish/dry with cotton cloth after each use. Each pour of tea is an additional layer of essential/tea substance deposit on top of each. Polishing/buffing is to evenly distribute these deposits. This step is to improve the cosmetic of a teapot, it has very little to do with the flavor of tea.
To conclude it all, the purpose of raising a clay pot is to enhance the flavor, improve the exterior beauty of a pot, extend the over all tea experience and a measurement of how obsessive you are about tea.
Clay pots are best for oolong and pu-erh. Green/white/yellow/herbal tea do not require the use of clay pot. Black tea is better in china ware. Porous pots are better with ching xiang fragrant greener type of oolong and new green pu-erh, ie duan ni or purple clay. Less porous pots are better for heavier roasted oolong, older/ripe pu-erh, ie zhu ni, xiao hong ni or chao zhou zhu ni. This is only a rough guideline. There are exceptions to rules, and there are surprises to exceptions. Experiment every possibility with every imagination.