What's the most effective method of treatment for plantars warts?

Combo treatment: Usually honing them down a bit with an emery board (then dispose of it) followed by a salicylic acid-containing solution (often found over the counter) and a band-aid nightly. This may help most to get better. If this is not successful the you should have a doctor take a look.

Ther is not just 1: Warts can be treated with topical meds, surgical removal, laser removal.

Several treatments.: You can try over the counter wart removers, but be careful: i've seen them do more harm than good. Other options your doctor might offer include cryotherapy (freezing the wart), electrocautery (burning the wart), laser treatment, or several different topical chemical treatments. If the treatment is typically uncomfortable, your doctor can numb the area before proceeding.