Check out this tip that demonstrates how to loosen a particularly stubborn bolt. Here's a hint: it involves using two hand tools.
How To Remove Rusted Bolts Without Heat
When you’re faced with a particularly stubborn bolt that just won’t budge, try locking together two wrenches and attacking that sucker again. The extra wrench will provide more leverage, hopefully enough to remove the bolt. Of course you could use a pipe, but the beauty of this tip is that if you have one wrench on hand, there’s usually another nearby. Try this little project for simple wrench storage.
