Thanks for the suggestion. I tried but still nothing came out. Had some black goo on the screwdriver when I pointed downwards through the drain hole but that's it. Looks like if all lighter stuff in the oil has evaporated and only the heavier stuff has remained. Not sure if it's better to flush all heavier stuff out or just top it off. But in that case I have two brands in it which I don't know if they will go together.
