(((Michel))) thank you very much for your kind words. I hadn't even thought of the dremel... I might try that. Will have to see though whether I can identify what you call the "soft stone" for that. May have to wait for the next pot to do that though as I wanted to pot a tree in that one this weekend...
P.S.: I did a bit of pottery some years ago but I must admit I didn't like what I made and with the last course I never saw how things turned out as I moved house...
This is the first time that I have tried to make bonsai pots though.