I recently purchased a 2005 CR-V EX 5 Speed. The coolant was green and of unknown origin so I decided to do multiple flushes with distilled water.
Draining the coolant is a slow process that I couldn't seem to accelerate. Since the thermostat is connected to the bottom radiator hose, the block can only drain through the thermostat's jiggle pin.
On the other hand, refilling at first was time consuming because I could only add less than half of what drained out and had to wait a long time for trapped air to escape. Then I found that removing the upper radiator hose from the radiator allowed me to pour in twice what I could pour in before and the whole refilling process went much faster. Also, I was no longer worrying about idling the engine with so little coolant in it while waiting for the thermostat to open.
I did about 4-5 flushes of distilled water before what drained out lost it's green tint. I refilled with Honda coolant.