The only thing sharp on a pipe cleaner is the end, so in this case you must have spun the wheel with the pipe cleaner not totally inserted, if you didn't do that, I wouldn't see how a pipe cleaner would do this damage, unless there was something sharp on the shaft of the cleaner (something I never noticed). However using the shrink tube on the cleaner is not a bad idea since it will limit damage when inserting the pipe cleaner. Looking at the wheel in the picture I don't think the damage is that bad, the scratch is going with the rotation of the wheel so you might not even notice it, esp for a scout race. If the scratch was going from one side of the wheel to the other (like you normally would get from inserting something sharp into the wheel) I would think twice about using it.