A measuring or rafter square is a great addition to any tool box. You can use it to mark a board for square or angled cuts. It fits securely into a tool belt and can be used to check the trueness of an angle or as a cutting guide for a circular saw. It's also handy when you're working with large-dimensional lumber or when you're laying out rafters.
For cleaning accumulated sawdust and wood resins from tools, use warm soapy water with a stiff scrub brush. If resin is a problem, you can try a solution of ammonia and warm water, but only soak parts in the solution a short time since it can cause them to rust. For grease or oil, soak parts in a good safety solvent.
Occasionally, deck boards need to be replaced due to wear and tear. Using rustproof deck screws when installing the boards makes the task much easier and it is best to replace entire boards. For stability and safety, a deck board should span at least three joists.