Hi John
Yes I did try the TDI at the time to see if I could get more consistency, but no dice.
I also looked into Al at the time (and I remember you discussing it), but I had no avenues of doing that either with evap or sputter. I did try coating both samples and standards at same time with Ag as well. Part of the problem might have been that I could only sputter coat the Ag which probably gave me a lot of islands.
I have an oxygen air-jet setup on the old SX51 which is not operational, but have no experience with it and/or how difficult that would be to install on the SXFive. I know people have had success with nitrogen trap/cold finger, stage heating, airlock plasma cleaner as well. I don't have anywhere near enough demand for the work to invest in them though.
Cheers