Take a single sheet and fold in half.
Fold in half again so it's a square again.
Tear off the corner formed by the two folds.
Hold the little piece and open the sheet back up.
The sheet has a hole in the center - put your finger through the hole.
Wipe/clean with the finger.
Wipe the finger off as you remove the sheet.
Use the little piece to clean under the fingernail.