เอามะพร้าวห้าวไปขายสวน เอาแป้งนวลไปขายชาววัง

Etymology

 * Literally, "sell ripe coconuts to the orchard, sell face powder to someone in the palace".
 * Literally, "sell ripe coconuts to the orchard, sell face powder to someone in the palace".

Verb

 * 1)  to carry coals to Newcastle (do something unnecessary, redundant, or duplicative)
 * 2)  to teach grandma how to suck eggs (to show knowledge to someone who is more knowledgeable than oneself)