check it out, my mother did it years ago, as advised just elevate the bin and puncture holes in bottom as well as sides.
for list of what can be composted which is what you put in your brown bin if you have one, anything that decomposes itself basically
in general it can take up to two years for compost to turn to fretilizer for you to use on flowers, etc. but you can scatter ashes mixed with potato peelings for example directly onto the ground where any bushes, flowers grow from
it translates as food to worms etc. as old and rotten fruit would and where there are worms you have healthy soil, etc.
good luck with it