Delete object cache--deletes the caché for selected non-Cloth objects. If an object is simulated as Cloth, and is then turned into a collision object (or inactive) vía the object properties dialog, it Will retain the Cloth motion in its cache.
This is useful for simulating Clothes in layers. For example, you may simulate a characters pants, then turn the pants into a collision object for simulating a Coat. By simulating in layers, you avoid the problems of Cloth-to-Cloth collision detection. If you want todo remove the cached motion from the selected object(s), click this button.