Is there a good do it yourself,and cheap, way to stop small tires from going flat? It seem most tires on small garden carts, hose reels, hand trucks,and other things just go flat over time. Is there a small foam doughnut or pump in foam that will work and that does not cost $40 a sniff? I have thought about getting a "noodle float" that the kids use in the pool and stick a piece in a tire just to see what happens. Or would a can of great stuff work?