Mix 60g potassium nitrate with 40g sugar in a saucepan over low heat. It's a 3:2 ratio, so if you don't have a method of measuring grams, use three tablespoons of potassium nitrate and two tablespoons of sugar. The sugar will carmelize and brown. Stir the mixture continuously until it resembles smooth peanut butter. I you are having trouble getting the sugar to caramelize, try adding some parrafin candle wax. Add just enough so that all of the powder in your pan is wet when the parrafin is melted. When using parrafin, there is no need to caramelize the sugar; just let the parrafin melt while mixing it and pour it into your tube once it's all melted and mixed. Remove the mixture from heat. Stir in a spoonful of baking soda (rounded teaspoon is fine). The baking soda is added to slow down the combustion when the smoke bomb is ignited. Add three large spoonfuls (3 tablespoons) of powdered organic dye. Blue dye and orange dye are said to produce better results than the other colors. Stir to mix well. Construct the smoke bomb while the mixture is still hot and pliable. Fill a cardboard tube with the warm smoke bomb mixture. Push a pen or pencil down into the center of the mix (doesn't have to be all the way to the bottom but should be enough that the pen stands in the mixture). You could use a different shape, but the cylinder works really well. Let the mixture harden (for about an hour). Remove the pen. Insert a firework fuse. Push pieces of cotton balls into the hole to tamp the fuse securely inside the smoke bomb. Be sure there is fuse left outside of the tube so that you will be able to light your smoke bomb. Wrap the smoke bomb with duct tape. Cover the top and bottom of the tube, too, but leave the hole area with the cotton and fuse uncovered. Go outside and light your smoke bomb!