Can i clean up a chimney pot thats been used as a garden planter to go back on the roof?

I'm having a wood burner open fire put in my terrace house and someone has taken the chimney pot off the stack. i want something that looks better than the normal roll top chimney pot nd have seen on ebay a nice "crown" chimney pot but this has been used in the garden for the past 20 yrs they claim. would it be possible to clean it up to go back on the roof and would be be ok for wood smoke to go through?