the silicone tube on the pick up float gets stained very easily, I usually soak it in sodium perc, this seems to help a bit but not perfectly.
I wondered what others do to clean it, or if it actually is ok with a bit of staining.
I soak in perc and i have a cleaning kit for a camel back, it's a tiny bottle brush on a flexible cable. Use it to clean the inside of the tube while still attached at both ends.
There is still a little staining but nothing like the browning of the silicon tube exposed to hot wort