Most commonly associated with stains but may be caused by a slow drying finish system. Deep stain penetration, especially in spring wood, causes slow curing of the stain due to the absence of airflow and oxygen. When humidity rises or with the application of a finish the cell structure swells causing the stain to be squeezed out forming a small droplet on the surface of the floor or film. Wiping with a dry, white towel normally identifies the presence of the problem which can be prevented by buffing with a red or white pad.