A brush having a handle and associated surface application portion, which brush handle contains a beneficial agent generator. The brush typically has a stem with first and second ends, the first end serving as a handle. Bristles are associated with the stem's second end. A beneficial agent generator (such as an electrochemical gas generating cell) that generates a fluid comprising an oxidizing agent is encased within the stem. For treating teeth, the generator will generally be chosen to generate an oxidizing agent such as a peroxide, ozone, oxygen, or mixtures thereof. When the generator requires it, the brush will also include a battery and a switch associated with the stem and in electrical contact with the generator. The switch may be associated with the first stem end and will be in operable (e.g., electrical) contact with the electrochemical gas generating cell and the battery. When the brush is used to brush teeth, it will generally also include a vent or port, in fluid communication with the electrochemical gas generating cell, for venting undesired fluids (e.g., hydrogen gas) from the second end of the toothbrush, such as the first stem end. The invention may be used in various useful methods such as cleaning, bleaching, and sanitizing tooth or other surfaces.