In warm, humid environments, the steel balls included with the Vernier Projectile Launcher (VPL) and Go Direct Projectile Launcher (GDX-PL) can corrode as they are not stainless steel. Since the balls need to fit very precisely in the barrel of the launcher, you should not attempt to use balls that show signs of corrosion. Also, do not try using any kind of oil to clean the balls as oil will damage the launcher.
If you have balls that have corroded, you can contact us for replacements.
Steel Balls (Set of 6), order code STB-VPL, $7
To help prevent corrosion, keep the balls sealed in an airtight container such as a zipper closure bag. If you live in an area that frequently experiences high humidity, consider including a desiccant packet in the zipper closer bag with the balls.