This disclosure concerns a method for removing gas and/or gas bubbles from a liquid medicament stored in a reservoir for an infusion pump device. The reservoir comprises a displacing member which is at least partly displaceable relative to the reservoir thereby enabling receiving mechanical oscillations in order to generate mechanical waves in the liquid medicament. The method comprises: providing the reservoir; and transmitting a mechanical oscillation to the displacing member of the reservoir thereby generating a mechanical wave in the liquid medicament for removing gas and/or gas bubbles from the liquid medicament.