A much better source of (virtually non-toxic) smoke is to use ammonium chloride, NH4Cl, and sparklers. Take a little tube, thin cardboard is best, put in some previously dried ammonium chloride (also called salmiac), and stick in three sparklers, next to each other, with the tip just sticking out of the ammonium chloride, such that they can be lit easily. When you ignite the sparklers, they will evaporate the NH4Cl, which immediately resublimes and gives an intensely thick white cloud of smoke. Prepare the smoke bombs a short time before using them and store them in a well-sealed plastic bag. They attract humid from air.
The attractive thing of this smoke "bomb" is that the smoke is non-toxic, or only marginally toxic, when inhaled in not too large quantities. NH4Cl also is an important constituent of many sweets, hence its relative non-toxic properties.
Even denser smoke is obtained by using thin PVC tubes with ammonium chloride and sparklers, but I do advice against those, because of the intensely toxic fumes, coming from the decomposing PVC. I would stick to thin cardboard.