A years play would probably see you ready for a new rod Paul. Especially if it wasn't changed after run-in at around 2 gal. I will send one down if you like ?

Lightly scrape the deposits off the piston crown with something plastic after a good dousing of brake clean (I use Repco brand and it's great). Then a good dousing of WD 40 and a blow off with the compressor. Coat everything liberally with after-run oil or similar and reassemble.

The pics of Treys GXII is what I would expect the internals should look like running a good tune with a decent fuel. It's all about the oil quality in the fuel.
We run Motul Micro oil in our PURE fuel. You won't find it in many, if any other nitro fuels to my knowledge (because of it's cost).
It is made "specifically" for use with micro engines running alcohol / nitro blends. It is an ester based synthetic oil and is totally miscible with alcohol and nitro, which most other 2 stroke oils are not. Very low ash content. We add a dash of high quality de-gummed caster for extra protection.
All you see when you pull down a motor running on this fuel is a nice golden honey coloured sheen over everything (the caster). No deposits at all - very much like Trey's pictures.
Some people here would call it backyard made fuel, we call it botique fuel .
I have run all my engines on this since it came on the market, and they are all in exceptional condition for their age.
No fancy packaging, no pretty colours, just good quality fuel with high performance results.
Sh-t, I should get a job in advertising eh