Clear Plastic Suction Cups and Airline Going Yellow?

When it's time to clean the co2 diffuser, I always get annoyed by the yellowness of the "clear" plastic items such as suction cups and co2 line.

Any ideas how to remove this?

 

have you tried bleach?

i use an old mug and bleach everything inc my DC. then i leave it to soak for a day or two with clean water. (plus a good rinsing)
in that time i have a cheap DC in my tank just to allow me to keep an eye.

 

Everything's been in bleach for a day, might leave it in there for longer.

 

hmm, thats interesting. well the normal stuff is bleach and a scrub but if that doesnt work then i really dont know.
i think leaving it for longer or in a stronger solution should do the trick though. (hopefully)

good luck to ya