I have a watch from some time in the 1960s that is labelled as containing 'Tritium'.  If it did originally contain the radioactive gas I can't tell, so now it just has phosphorescent hands and hour indicators which glow for a time as you go from a brightly lit room out in the nighttime (or after you turn out the lights going to bed).  I guess they might have originally been energised by particle emission from the gas which has long since escaped (despite it claiming to be 'super waterproof 200' but I guess even tritium atoms are smaller than water molecules with their oxygen wings).  But after less than a minute the luminance fades, so I know it's not still radioactive, if it ever was.