The clay infusor is broken!

I don't know if this was during the transport or if it already was this way, but i am seriosly bummed about it because its a wonderful clay infusor, and clearly part of the original pot.
It's the kind that goes in the top of the pot and you fill it with leaves, but this is the first time ive seen such a thing in clay and the volume is quite large.
It's still useable but it has two big 2 cm chips in the top

Because of this filter im not sure it was used as a kettle. At least it was a combined kettle / teapot.
The actual teapot is in much better shape, some minor scratches at the bottom.
And the inside of the teapot is quite dirty, but i think this can be more or less salvaged.
I would like to know what kind of solution you "experts" (at least compared to me) use to clean old yixing pots with?
Also from this layer it would seem to me that the pot is at least 5 years old (but i could be wrong). It is also possible that it is actually 60 years old, after all that was what the vendor described it as, and i think its at least POSSIBLE that they weren't lying
About the handle i tihnk you are right that its a substitute, it doesn't seem like a part of the original pot.
All in all im very happy about this pot, but im also quite disappointed about the filter.
There is stamp on bottom of lid and pot, but i don't know what they mean.