Review on Color Changing Reusable Plastic Tumblers with Lids & Straws - Large 24oz Cups 🥤 for Adults, Kids, Women - Party, Cold Drinks, Drinking Tumbler Cups - Bulk Set of 9 by Brian Garrett

I bought these and they never changed color so I ended up returning them. After I sent them back, the seller contacted me to find out what was wrong with the order. They sent me a new pack of mugs to try. These new mugs have changed color and are very bright and vibrant! First I washed them with soap and water, then I added hot water and let them sit for a few minutes. I rinsed them again and added ice water and they changed color. Be sure to add ice. The more ice, the more they change. This seller's customer service is top 5! I highly recommend them.