a method of making a body cavity insert , e . g . an ear insert , comprises deforming by pressure a pressure deformable sheet of material over an impression of a body cavity , e . g . an ear canal , and separating the impression from the sheet of material without permanently disturbing the shape into which the sheet has been deformed to leave a mould cavity in the sheet of material . a moulding material is then introduced into the mould cavity to provide , when the moulding material solidifies , the body cavity insert . typically the pressure deformable sheet of material is a sheet of non - toxic , thermoplastics material , e . g . a polycarbonate or silicon rubber material . one example of a suitable moulding material is an acrylic plastics material .