A question about ashes

A reader writes:

I attended the 9 am Ash Wednesday Mass this morning, after which I went
almost directly to work at 11 am, and worked until about 8 pm. I kept
the ash on my forehead the whole time. All day long I got comments from
co-workers and customers, mostly saying something to the effect of,
"What's that on your forehead?" One co-worker even said, in a somewhat
hushed tone reserved for those who have forgotten to zip up, "Um, I
don't know if anyone's told you, but you've got something on your
forehead." (By that time, the shape of the Cross had smudged away
somewhat.) Out of all the people I encountered who made reference to it,
only one customer knew what it was, and matter-of-factly asked me if I
knew what time the evening Mass was going to be.

Now I've never been to a Catholic church up until I
started the RCIA classes a few months ago, but I have been in Lutheran
churches which have a very similar service on Ash Wednesday (I actually
attended a Lutheran high school), and the tradition there was, you kept
the ash on your forehead all day, or until it wore off, whichever came
first. And everything I read since then implies, although never directly
states, that as Catholics we do the same. However, my wife, who grew up
Catholic, says she never heard of keeping the ash for the whole day and
seemed surprised I had done it.

So, please tell me, which is it?

I think it depends on who you ask. Last night, Cardinal O'Malley said in his sermon that he'd been pleased to see so many people during the day with ashes on their foreheads, proclaiming their Christianity.

On the other hand, a deacon once told me he thought keeping the ashes on went against yesterday's Gospel injunction against appearing ostentatious in piety.

I tend to hold the Cardinal's view, although I sympathize with the deacon's.

(Frankly, I'm rather amazed that so many people didn't realize what the "dirt" on your forehead signified!)

In any case, it's important to remember that the ashes you received yesterday are blessed, and as such, should be reverently disposed of. I was taught to carefully remove the ashes with a tissue, and then burn the tissue.

Anybody care to share their thoughts on this? Thanks!