I want to craft something that requires water, but there is residual seed oil in my carpenter. How do I get it out?
Use the pipette. It'll remain in the pipette for re-use later (or for any other forestry machine e.g. the BioGasEngine). The display of the pipette is a little bit buggy though.
But - it's a pain in the ass because you need one pipette for every type of liquid. I prefer using a carpenter for each type of liquid.
The third way should be pumping the liquid out using liquid pipes - but I haven't tried that.