Your starter is desperate to be refreshed if it smells of nail polish remover (acetone) or, even further down the line, old cheese (butyric acid). The sad truth is that the esters in your starter, whilst delicious, are in part due to the alcohol produced by yeast fermentation because it is too mature to use. The esters actually contribute little towards final bread flavour, and you will end up with an underproved and heavy loaf. Refresh your starter back to back at least three times before you bake.
