My 68 has a space saver spare. It doesn't appear to have ever been used. Somebody tell me about these things. Are they one and done or are they reusable? How do you shrink them back to being a space saver? I'm assuming they can be reused. What about the inflator? Is it refillable? I'm wondering if I should test mine out. If it's no good it's just dead weight in the trunk.