Both oil and gas boiler produce soot. The soot should be cleaned from the boiler at least once per year, or when the soot builds up. This ensures that the boiler functions properly, while using the least amount of energy possible. After the soot is removed from the boiler, it should be properly disposed of.
Allow the soot to cool to room temperature.
Sweep or use a shop vacuum to vacuum the soot. Discard of the soot into large trash bags. Do not do this while the soot is still warm, or it could melt the plastic or start a fire.
Place the garbage bags out for garbage collection. Boiler soot can be disposed of during your routine garbage collection, or it can be taken to your county or city dump.