methods and devices for recharging glow - in - the - dark fishing lures . devices can include an internal cavity , an external opening into the cavity and a light source projecting into the cavity . some cavities have an opaque , reflective wall and a light source projecting directly into the cavity . other cavities have a translucent cavity wall and a light source shining in from outside of the cavity , through the cavity wall , and into the cavity . the light may be activated using a manual switch or an automatic switch which triggers upon detecting the passage of a lure into the cavity or the presence of a lure within the cavity . one such lure detector includes a weight sensitive electrical switch . devices may resemble hand held mugs with handles or may be flange mounted into through - holes in boats decks .