The Paxman Pull-Through is made from plastic coated wire with a brush at either end. Primarily for use in cleaning the mouthpipe, it is also capable of cleaning the rest of your horn tubing.
To use it, remove the mouthpiece and the main tuning slide. Push one end of the Pull-Through into the tuning slide end of the mouthpipe and carefully feed it through until it comes out of the mouthpiece end, in other words from the larger to the smaller diameter. Then gently pull from the mouthpipe end until the whole Pull-Through has come through.
Rinse the Pull-Through and repeat until it comes through clean. If the mouthpipe has not been cleaned for some time, the first cleaning may result in a rather unpleasant spectacle - an indication to clean the mouthpipe more regularly.