A reader writes:
Tonight my family and I went to Ash Wednesday Mass. We came home and immediately prepared ourselves for bedtime since it was already way past kids' bedtime, and I wondered what to do with the ashes on our faces. If Ash Wednesday Mass is in the morning, then typically the ashes gradually fade over the course of the day, and so I don't feel bad to wash the residual ash off my face-- the ashes served their purpose most throughout the day. But this evening when I arrived home it seemed disrespectful to immediately remove the ashes that had only been on for 30 minutes and unseen by anyone outside church.
My wife stuck to her extensive face-washing routine, and I (hey, I'm a guy) left my face 'as is', with the exception of some gentle and reverent blotting to clean off excess ash that might soil the bed linens.
Does the Church teach specifics how to treat the ashes once applied to the forehead? For example, how long should we wear the cross on our forehead? And in what manner should we wash-off?
The Church does not require us to get ashes on our heads in the first place. It's a custom, but the individual members of the congregation are not bound to go forward to receive them.
Neither is there a mandate about how long they should say on. If they stay on for a long time and others see them then that is a side benefit, but their real purpose is to remind you of your mortality (hence what the priest says when he puts them on you) and your need to repent.
Once that goal is accomplished, you can wash them off at any time--especially to avoid things like getting them on bedsheets--though if you can leave them on longer then it is a good public testimony to one's faith.
I would definitely not have them on the day after Ash Wednesday. Then you'd look like a nut and the good of a public witness would be undone.
There also is no specific manner mandated for washing them off. Just don't be deliberately respectful as you do so.
Incidentally. lightly blotting the ashes would have never worked for me yesterday. So as to be a better public witness, at Mass at Catholic Answers, Fr. Serpa put BIG BOLD BLACK CROSSES on everyone's foreheads, not the customary small grey smudges you get most places. We had ashes falling on our clothes all day, and the ashes were so dense that there would have been plenty left to get on my pillowcase if I hadn't washed them off first.