I know this is a bit indelicate, but it's a real question.
In the offering of Mass according to the Extraordinary Form, the priest must maintain "custody" of thumbs and forefingers from the consecration through the ablutions.
Now let's say it's summer in the humid Hudson river valley. It's hot in church. Some parts of Father's body--"Brother Ass" as our holy father Francis called his--are covered in five layers of clothing and vestments. In the time between the consecration and the ablutions, it would seem outside of the spirit of the rubrics to pull one's hanky from one's cincture or sleeve, much less wipe one's face while maintaining custody of thumbs and forefingers. But then what do you do when, by the time of the prayers before Holy Communion, the sweat is stinging your eyes and you can't read the missal?
I am told this is what the maniple is for...but I don't want to wipe my sweaty face with fancy stitching, and much less with a representation of the Lord's Cross! Could a server do it, like someone might do for a surgeon?
I know this is kind of gross, but it's the sort of practical question that just presents itself!