What would be the point, then, of receiving ashes on our foreheads on Ash Wednesday if not to wear them during the day? If we weren’t supposed to show them, then why not put the ashes on the back of our hands? Once they’re on your forehead, how can people not see them? I’m certainly not going to get ashes and then go home and wash them off.
All I can say is that someone on WDTPRS said that he or she was catechized as if washing them off was not only an option but was recommended if one perceived that wearing them would be an occasion of the sin of pride. Even good things can become occasions of sin, even spiritual things can, if done out of sinful motive, become sins.
It’s good advice—for all of us, not just Joe Biden.