It works for me: the "button train" !!
I call each table of 5-6 kids to the paint shirt box at a time. I quickly
slip a shirt backwards on each kid. The kids go to the side of the room, one
behind the other and button one button on the kid's shirt in front of them,
and then go sit down. I can get paint shirts on 30 kids in 5 minutes. All
of the shirts we use have short sleeves and buttons (as opposed to pull-over
shirts which more easily pass potential lice from head to head !!) I think
they do help keep my students slightly cleaner...