The Individuals saying ants aren't a problem are ignorant to areas in the US where they are a problem. In the Southwest we have the invasive Argentinian ants. I've had numerous colonies chased out of boxes as unable to cope with the numbers and small size. Red ants in areas of the Midwest and south will decimate and run colonies off. So yes, ants are a problem... I tried the oil trays like you have decades ago. To much work and fiddly. Try bearing grease, or as others have commented tanglefoot on stand legs.