I didn't do anything but put my r22 guages on the 410a system. Im embarrassed to tell you I am 410 certified but that was a year ago and this 410 system was not marked. Did I contaminate my guages and the 410 system??
It is unlikely that any oil contamination was done. The pressure of the refrigerant pushes the gas and any residual oil into the hoses and gauges. In order to push that content back into the system, the pressure in the gauge would need to be higher than the system. Most of us remove the hose from the schrader and the gas in the hose is a deminumis loss of refrigerant.
It is possible that either in a charging hose or if you back pressured the hoses with a recovery compressor wouldyou be able to get flow back into the system. Even in that case the miniscule amount of oil would do no harm. Unless the hose was filled with oil.
I'm 410 certed also and very small amounts of mineral oil will not damage anything.
You could mix as much as 5% mineral oil with POE oil and not have a problem. Lab tests with even greater amounts of mineral oil mixed with POE oil have been done with no appreciable problem even with extended testing.