Prior to the arrival of the Spanish, Chinese settlers pioneered a still-active pottery industry. You can visit a couple of pottery factories on Gomez St. The 50m-long kiln at RG Jar, which was made in 1823 and can hold nearly 1000 jars, is a wonder to behold. Local potters let you create your own misshapen ceramics at the pottery wheel.
You can buy a small clay souvenir afterwards. The burnay (earthen jars) that you find here are used in the fermentation of basí (sugar cane wine) and bagoong (fish paste), but you are more likely to see them scattered about in homes and gardens.