As you can see in the last picture, the can definitely left a rust ring on the glass, and even that took some scrubbing to get off. Make sure you put the can on something so it won’t stain your crockpot. I tried two different brands of sweetened condensed milk, just to see if there was a difference. The consistency of Nestle Carnation was very smooth, just like what I was expecting. I also tried Eagle Brand and it was more the consistency of sour cream, but the taste itself was similar.