tlaolchachapatztli.

small drops of liquid rubber (olli, ulli), put on white paper flags (amatetehuitl) during a ceremony in the month of Quahuitl Ehua or Atl Cahualo, which was devoted to the rain deities
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 2 -- The Ceremonies, No. 14, Part III, eds. and transl. Arthur J. O. Anderson and Charles E. Dibble (Santa Fe and Salt Lake City: School of American Research and the University of Utah, 1951), 42.