Can parishioners give each other ashes on Ash Wednesday?

It is true that lay ministers can be deputed to assist a priest or deacon in the distribution of blessed ashes: “This rite [the blessing of ashes] may be celebrated by a priest or deacon who may be assisted by lay ministers in the distribution of the ashes. The blessing of the ashes, however, is reserved to a priest or deacon” (Book of Blessings 1659). Leaving the ashes unattended on the altar for people to come in and give to each other is not provided for by the rubrics and should not be allowed.