I have avoided olive oil for many years and prefer soaking them in distilled water for a month or so then changing them out and scrubbing them with a toothbrush that has been cut down to make the bristles stronger
make sure to clean the containers well when they get grody - I use vinegar and rinse thoroughly
I often boil them in baking soda and water , scrub after
sometimes I let them soak in
dish soap and water for a little while
it looks like your coins are practice coins and I wouldnt expect much
I have
had great
success buying coins that need sprucing up as the truly uncleaned coin market is pretty hard to achieve, most are sorted, many are re dirtied
good luck!!!