Look, I'd rather use paper liners, too. But I bake low-fat Weight Watchers recipe muffins and they stick like mad to the paper. I got these with a 50% off coupon from Michaels (ergo, $5). Directions say wash first in hot, soapy water (check), dry thoroughly (check), Spray with non-sticking cooking spray (I put a drop of vegetable oil in each one and spread that out with my fingers) Muffins didn't stick, soaked the cups, washed with soapy sponge (check). Perfect.
2014 and I still love these cups. They stained a little because I bake a lot of pumpkin muffins, but that natural coloring doesn't bother me.
To those having trouble "de-cupping" -- did you think they were just going to JUMP out of the cups? Not even the paper ones do that! Yes, you have to tease them out a little (try peeling around the edge first), but then they "un-cup" just fine.
Filling tip: Use an ice cream scoop (disher) that holds 3 Tablespoons. If you want cupcakes that are just slighly crowned, almost flat: fill the scoop level. If you want muffins that are high and very rounded, overfill the ice cream scoop. I bought a scoop for $14 in the neighborhood that broke the second time. Now this Oxo is my "go-to" --