Gail and Doedo Schipper tried out a new smoke oil technique last week, flying from Longmont, CO: We tried the smoke system with transmission fluid as per the Feb EAA magazine. This was cold filtered gently used oil. It was free. Seems to work just fine. It is still cold here withe ice and snow everywhere. Came very close to two flocks of geese squatting on the private grass runway south of Longmont.