Abstract: A vertical compactor has a frame with legs spaced to receive an upwardly opening dumpster or similar container. A compactor head mountable on top of the frame has a feed inlet for receiving material and a ram pivotable downwardly into the container. The frame has two parallel guide members slidably supporting the container and opening at flared flanges on both opposite sides of the frame. Thus the container is insertable and removable from either side. A remountable stop is attachable to at least one of the frame and the compactor head to close one side such that the container can be inserted into the other side and slides up to abut the stop. The stop can be a cross bar extending between ends of upper structural rails, remountable on either end of the rails, for example using a shackle and pin coupling, and/or can have holes aligned with holes in the compactor head for receiving fasteners.