A method for blowing synthetic resins as a fuel into a furnace comprising: processing synthetic resins consisting essentially of film shaped synthetic resins by melting or semi-melting the synthetic resins by heat to produce granular synthetic resins having a bulk density of at least 0.3 and angle of repose of up to 40 degrees; pneumatically feeding the granular synthetic resins from the processing; and blowing the pneumatically fed granular synthetic resins into a furnac