That's true, where can I buy one of these sticks?
Not being a plumber, I can only guess a length of small diameter copper pipe would be suitable. I have a very vague impression a gas pipe is small. Other options could be a coat hanger wire. If made sharp, this could be very pokey. For a more pro set up, the stuff from the loose metals bucket at B&Q could work - a rod of aluminium, mild steel, hard steel all should be available. If the pipe to be unblock is large enough, segmented 15mm plumbing pipe could be used for poking and aided with a hammer. But preparation has to be made to allow the segments to be extracted afterwards.
