Kohler Toilet Seat (Antimicrobial) – Costco Sale! by Rhonda June 14, 2022 June 14, 2022 *UPDATE* 6/14/22. This Kohler Toilet Seat from Costco takes clean to the next level with an antimicrobial agent that protects the toilet seat from odor- and stain-causing bacteria, mold, and… 0 FacebookTwitterPinterestEmail