Very good ideatsusentei wrote: I actually use the items shown by WYARDLEY. These will not damage your pot, as long as you are careful in their placement. These are meant for pots with a single large hole on the inside of the pot. You can install one simply and safely with a plastic straw. Fold the plastic straw in half lengthwise and insert it through the spout. Pull the inserted end out of the top of the pot and insert the tines of the filter into the end of the straw. Pull the straw back out of the spout, dragging the filter into the interior of the spout from the top of the pot. If this is unclear I can try to draw a picture.
Funny, the minutia one must deal with just to drink a bit of tea (^^)

I've used similar principle by tying the wire of the filter with dental floss, making the coverage area at the tip of the wire narrow and install the filter into the pot easily. The dental floss was removed easily by pulling it out of the spout.
Unfortunately in my case the problem starts to appear as the pot used intensively over couple of weeks. It became instable, most likely because of the shape of the spout and I found bits of pot's clay inside the pot after sometime. Since it's only 2 mm thick pot, I'm horribly afraid of it and I decided to remove it.