Walmart's Free Eyeglasses Cleaner

I'm getting low on cleaner for my glasses. I got the little bottle of it at Walmart. They have an interesting policy on this. If you buy it once, you can keep bringing in the bottle and they'll refill it for free. I think we might be on about the fourth or fifth filling.

Why do they give it away for nothing? I have no idea. But I notice they haven't extended that policy to other things. Which would definitely help me save money if they did. Like cat food. You could bring in your old cat food cans and they'd refill them. Toothpaste tubes. Shampoo bottles. Floss dispensers. "I'm here for my free refill."