Heres my latest update on the sticky knob problem......
Best solution so far is. ..... nail polish enamel!
The stickiness is apparently caused by decomposition of the plastic and the internet is full of bloggers asking the same question - how to clean it off. It has been widely reported problem on camera cases, guitar stands, car boot release mechanisms - and nobody has a good answer on how to fix it - apart from replace the plastic or rubber component. Once decomposition has started, not even cooler climate with harden it up.
No household cleaner I tried works, and it is reported that most solvents (acetone,methanol,toluene) make it worse apart from possibly Isopropyl Alcohol (propan-2-ol) which is now hard to get because it is apparently used in the manufacture of illicit drugs.
So I experimented with nail polish to put a hardened seal coating over the stickiness. I painted my Hercules microphone stand grip - and so far it has worked, however it is early days yet. If this coating stays dry and hard in the long term I might use it on my Tonematch knobs.
And just for the record, the colour I used - carribean sky blue. 🙂
Ok. So I've actually done it now to a spare retired T1. I have painted the 3rd selector knob and the phantom switch. I have left the 1 & 2 selector knobs unpainted for comparison. I will observe this over time ( years) to see if the knobs deteriorate.
As of now, the painted knobs are perfectly functioning and easy to use, and feel better to touch than the unpainted sticky knobs.
Explanation notes. I have five T1's. Three were purchased in Australia, one purchased in USA - between 2008 and 2010. The newest T1 is a 2012 unit which is a replacement unit for a T1 damaged in an electrical storm and paid for by my home insurance company.
All four of my original (2008-10) T1s now have the sticky knob problem. The 2012 replacement unit is not yet sticky.
This 'test' T1 unit was the one damaged in an electrical storm, the surge came thru the USB connection to computer - we lost much computer gear that day. So now I have a spare T1 that I would never use for a live performance - but I'll try knobs on. 😉