Wool clothes were cleaned and bleached by treading in vats filled with a solution composed of water and stale urine. This was not a very pleasant task and was probably performed primarily by slaves. The smaller figures holding the cleaned clothes may be child slaves, or they may be older workers depicted on a smaller scale to save space. After this operation the clothes were washed in large vats and hung to dry.
White garments were spread over large wire frames (vinimea cavea), like the one depicted above, under which sulfur was burned to bleach the cloth.
After cleaning and bleaching, the wool was carded and brushed to smooth it and raise the nap. Finally, the clothes were pressed in a wooden frame with two upright screws as shown below and then folded.
