First, please explain to me why this is a problem that should even be discovered during Mass. Do not most people take care of this problem during their morning routine? Should not their attention during Mass be focused on the altar and not on their personal hygiene, which should have been taken care of before leaving for church? Frankly, it seems possible to me that many people are looking for loopholes to the Communion fast. If that is the case, then they really need to re-examine their understanding of the Real Presence of Christ in the Eucharist and their devotion to our Lord and to his suffering on the cross for our salvation. If they do so, then perhaps they will not be so concerned with examining minutiae of just what is and isn’t allowed to be eaten or drunk within the hour’s fast before reception of Communion and will concentrate instead on doing their best to avoid all food and liquid (excepting water and medicine) without unnecessary scruples or undue exceptions.