Playtex Insulator Spill Proof Cups Review

I have been a child care provider for 14+ yrs now. I have always been a fan of the Playtex line of cups. However, I used to be able to buy replacement valves, and can no longer find them at my local WalMart or Target, leading me to believe they don't sell them separately any more. It's a shame having to fill our landfills with cups when the only thing wrong was that the valves were worn out, making the cups no longer spill proof. The cups can easily last 2-3 yrs or more, and the valves tend to last about 6 mos or so with regular use.

Also, because I provide child care in my home, I would like to see more variety in the colors / designs, I have found these in 4 colors, but I care for up to 5-8 children at a time, and I'd prefer to have 1 type of cup, in an assortment of colors / designs.