...Ethylene oxide is a gas.
It is produced (for example) by ripening bananas and signals other bananas to ripen.
Please explain to me, how a gas will be administered by a swab?
It is used in the sterilization process for mass quantities of devices.
The put the boxes on a pallet in the chamber. they include a known bacterium sample in a few places within the pallet for a confirmation purposes that the sterilization works. The flood the chamber with EO under pressure to force it into every nook and cranny. Then they flush the chamber with clean air. Then they let it sit for a day or so to ensure all the EO is out. Then they remove the product. Then they check to ensure the test bacterium died before allowing release for sale.
EO will leave a residue on the product, and if your are exposed to it a whole lot that residue cold build up over time.
Interestingly because it’s also explosive the test chambers are specially built with the weakest part being the ceiling/roof to ensure that if a chamber explodes the weakest point will give and the force will go up and not out.