Grater plates (or ralladores) are wide flat dishes crossed by deep grooves, sometimes wide and deep enough for your finger. In 2003 I had a conversation with a colleague who works in the Near East, and they opined that a grater made from clay would probably not work as a processor for foods. So later that year in Santa Ana we gave it a try, using two grater plates to turn several kinds of vegetables into pulpy mush: corn, cassava, carrots, beets, and several others. Georgina Bocchietti of the Museo Yacuma (wow! check out their new front page) is grating, I am taking notes, and two of Georgina's grand-nieces and nephews look on. Of course, this doesn't prove that pre-Columbian Mojeños used ralladores for processing cassava (for example), but it does establish that they could have. Soon we hope to answer the question more directly by analyzing the residue left behind on ralladores and other ceramics, to see what kind of foods might have been prepared.