No, not really hard, BUT moving the can in such a fashion that the ball hits the same basic spot repeatedly, coupled with the fact that I "whip" the can back up which then slams the ball against the bottom, rather than "rattling" it. There were two people that have not yet been back over here to see (or at least not posted in the thread) that were certain it was not the shaking, and I know it sounds silly, but I really want them to see it. LOL The Testors discontinued line of CreateFX washes and stains in the 1oz glass jars often had little agitators in their bottles. While shaking one of those one day, I cracked the jar, and started to sling paint. I am just glad it did not shatter and send paint flying all over my projects. sooo, I am way gentler on those, moving it around, more of a swishing motion now.