Fat when combined with acid forms soap (which dissolves in water).
So, scrub the container with a used lime/lemon/orange (citric acid)
peel and rinse it out. Vinegar (acetic acid) would work too.
(It should work ... but, no guarantees.)
=====
-- Sajjad Lateef e-mail: sajjad_at_acm.org Note: Any e-mail to me with my first name in Subject or without a subject line is automatically filtered out and discarded as s p a m . /----------------------------------------------------------------------------- /"Unless stated otherwise, comments made on this list do not necessarily / reflect the beliefs or goals of the North American Native Fishes / Association" / This is the discussion list of the North American Native Fishes Association / nanfa_at_aquaria.net. To subscribe, unsubscribe, or get help, send the word / subscribe, unsubscribe, or help in the body (not subject) of an email to / nanfa-request_at_aquaria.net. For a digest version, send the command to / nanfa-digest-request_at_aquaria.net instead. / For more information about NANFA, visit our web page, http://www.nanfa.org