I cribbed 油 from the ventilator hood over our stove, which has a large advertising sticker proclaiming it to be a 吸油烟机 (xīyóuyānjī: lit. “grease smoke sucking machine”). All the appliances in our apartment were new or newish when we moved in, and neither our landlady or the previous tenant (or, indeed we) had removed the showroom stickers touting their virtues.
油 takes the radical 水 (shūi: “water,” in radical form simplified as two dots and a stroke on the left of the character), which usually signifies a fluid or body of water. The sound part, helpfully, is 由 (yóu: “from”). So in the case of 油, both the radical and sound-part are actually useful.
Spectators of sporting events shout 加油！ 加油！ (jía yóu: lit. “add oil”). This is also how you say “fill one’s car with petrol.”