A method to manipulate a well comprising providing an apparatus (60) in a well (14) below a packer (22) or other annular sealing device, the apparatus comprising a container (68) having a volume of gas which is sealed at the surface and nm into the well, such that the pressure in the container (68) is at a lower pressure than the surrounding well. When the apparatus is below the packer, a wireless control signal, is sent to operate a valve assembly (62) to selectively allow fluid to enter the container whereby at least 50 litres of fluid is drawn into the container. In this way, the apparatus can be used independent of perforating guns, to clear perforations or other areas in the well or may be used for a variety of tests such as an interval test, drawdown test or a connectivity test such as a pulse or interference test.