If your bin smells bad
It's normal for bokashi bins to smell slightly acidic. If it smells bad then your scraps are probably rotting instead of fermenting.
Bury your rotting waste in at least 10cm of soil in the ground or a large pot of soil, wash the bin thoroughly, and start again!
To keep this from happening in the future, make sure you:
close the lid tightly
add enough enzyme spray
tap out bokashi juice frequently
keep the bin in a relatively cool area
If you see white mould in the bin
This is normal and a by-product of good bacteria breeding. You don’t need to change anything.
If you see black or blue-green mould in the bin
This means your waste is rotting instead of fermenting. Follow the instructions above under “If your bin smells bad”
In order to minimise unpleasant odours or blue-green mould in your bokashi bin, try emptying it every 3 weeks even if it's not completely full.