Smoke! in a Can
Aerosol Spray for Functional Testing of Smoke Detectors
NFPA 72, Table 7.2.2, states that "detectors shall be tested in place to ensure smoke entry into the sensing chamber and an alarm response." Smoke! in a Can lets you meet this requirement without contaminating the detector, without affecting its sensitivity and without increasing the risk of false alarms.
Link to this product
For web page (with image):