If you're thinking of using metal fence posts to hold up a tarp, old tennis balls work well as metal post caps.
Metal fence posts make great frames for stacked firewood. But I’ve been frustrated by the holes the post tops often tear in my wood-covering tarps.
The solution? Tennis balls.
I simply slit an old tennis ball and slip it over the top end of each post. Now, when I throw a tarp over the stacked wood, the metal post caps serve as tarp protectors. They provide a cushion that keep tarps from tearing.
I have found free or cheap “dead” tennis balls (balls that have lost their bounce) at tennis clubs and thrift shops.