Great tips here, a fuel filter is definitely a must IMO. The little Dubro inline ones work fine for me. Traxxas Top Fuel is good stuff, it doesn't gum up too badly, but it still can. As said above, run it totally out of fuel when you plan to let it sit for longer than a few weeks. Capping off your engine for storage is also a good idea. Basically it's a set of rubber caps that cover the fuel inlet, carb venturi, and pipe stinger. That along with after run oil helps a lot to stop the gummy crud and will also keep the internals from corroding from long storage times. Nitro fuel can cause extreme corrosion if left to sit in an engine. You can also find vacuum line caps at most auto parts stores that work well for plugging up the engine. For cleaning, denatured alcohol works really well at dissolving gummed up fuel.