Put on a long-sleeved shirt, work gloves, protective goggles and a dust mask to protect your skin, eyes and lungs from insulation particles and fibers.
Cut holes every 3 feet along hollow areas of the walls, ceiling and floor with a keyhole saw, working in inconspicuous spots whenever possible. Save the cutout pieces so you can patch the holes up later. Make the holes just large enough to fit the vacuum’s hose through. If the insulation is already exposed, you can skip this step.
Insert the vacuum hose into one of the holes, turn it on then vacuum out the insulation. When removing insulation from walls and ceilings, start with the topmost hole and work your way down to the bottom.
Apply caulk to the edges of the pieces you cut out of the wall, ceiling and floor and replace them. Allow the caulk to dry then sand the patched area flush with the surface. Coat the patched areas with drywall compound and smooth them down with a putty knife. After the compound dries, feather the edges with sandpaper to make them flush with the wall.