Cleaning tubing for PISA

Jacqui105

I have the Medela PISA, used it for almost a year with DD1. Now, starting to use it some for DD2 in prep for going back to work. The tubing looks cloudy near the connectors and I want to see if I can clean it or need to replace it. How do you clean your tubing? The manual just says soapy water but I thought I've seen mention of boiling, running rubbing alcohol through, etc. What is the best way to clean them in your opinion?