I get the bulk out with an oil extractor for cleanliness (most drain containers are only about 5 litres too) and then get the last 1/4 litre or so out from the sump plug. A new plug is less than £2 and just torque it up to 30Nm and all is good. I'm replacing the filter from underneath anyway so have to remove the bottom cover so it makes sense to do the job properly.