Insect cells don't have a cell wall and therefore lyse rapidly. The most used method is disrupting the cells using a Dounce homogenizer in the presence of a low concentration of detergent (0.1% Triton X-100 or NP-40). Usually 10-20 strokes from the homogenizer are sufficient. If the volume of the cell suspension becomes larger than 25 ml, an electric homogenizer should be used.