Older style bumper caps such as those on passive bumpers often are loose and
rotate during play so that the lettering appears crooked. These can be
lightly secured with a small dab of silicone adhesive on the underside of
the cap. Or you can place a very small strip of tape on the inside brim of
the cap so it fits tighter on the bumper. These two methods still allow you
to easily remove the cap to replace the light bulb, yet are enough to keep
the cap from rotating.