Is it possible to get HIV by masturbating inside dirty public toilets

I have masturbated inside dirty public toilets several times. Is it possible to get HIV just by masturbating several times as the place was dirty or the hand used for masturbation was unclean. My fear is that if there was HIV infected bodily fluids on door knob or toilet seat covers or any other things which I touched unknowingly and used the same dirty hands to masturbation. I never had sexual intercourse or intravenous drugs usage till date.