Alexander Moritz Frey, who served with Hitler during World War I, said Hitler wore the toothbrush in the trenches after he was ordered to trim his moustache to facilitate the wearing of a gas mask.
Alexander Moritz Frey, yang bertugas bersama Hitler saat Perang Dunia I, menyatakan Hitler mulai berkumis sikat gigi setelah diperintahkan untuk mencukur kumisnya demi memudahkannya dalam memakai topeng gas.