Along those lines, but probably not enough to start a separate topic, a champagne cork makes a good pipe knocker
glued to the bottom of an inexpensive ash try or any inexpensive (or priceless?) fireproof dish with high sides.
If you don't want to glue it, you can just hold it with one hand and knock the pipe with the other. Or if you can
drill a neat hole in the bottom of the dish without cracking it, a screw will hold the cork in place. A champagne
cork is especially suited because it has that flared base and rounded top. You don't need to knock the pipe
hard, just enough to knock out the loose pieces after you've cleared the bowl with a pipe nail or tool.