Yeah, grating and juicing and then freezing is probably best, but there are just some times that I just don't have that many spoons. I'm glad to know I can just chuck them in the freezer.The limes I froze were sad, and the rinds weren't worth grating. The juice was still good after defrosting.
In hindsight, I would probably grate off the rind if the limes were fresh, and then freeze the naked limes in a ziplock. Or just juice and freeze.