Jo,
Many thanks will try your suggestion. I guess rather than change the solution in the ultrasonic cleaner I could just but a glass jar (large coffee jar or similar) of paraffin in (sat in the basket) and put the gauges in that.
Must admit very dubious of taking them apart.
Colin
PS Now have set of metric collets from 1 to 10mm plus a few other metric and imperial for the Aciera. Just need to find a 3/8" now. 4 jaw chuck now fitted to W12 mandrel. Slowly but surely its coming together.