I am altering a bathroom basin waste that involves connecting to a dedicated old upvc solvent weld 32mm pipe. I intend that the new work is all solvent weld connected to the existing pipe. I read that new pipe & fiitings do not require a cleaner but how do I prepare the old existing pipe for a slovent weld fitting? I have not found a shop that sells a cleaner, apart from a cleaner for windows etc. Any advice gratefully received.