Is there something you can do to "refresh" the slickness of the a nickel-plated needle? They're the KP ones and I just switched sizes to start a new sock and this other size just doesn't feel as slippery. There's nothing visible on the surface of the needles as far as I can tell, they just don't feel the same. Any tricks for that? I know wax paper for wood and bamboo, wasn't sure if there was anything for metal.