[AKnowles]

I'm in the drain the oil while it is hot camp. For two reasons particularly:

1) Particles have a tendency to be picked up better by hot oil and flushed with the oil change.

2) Sludge does not even move when cold. The "sludge" generally contains the most particles.

Depending on vehicle age, oil type, oil change frequency, etc. you might be surprised by what is left on the bottom of your oil pan just waiting to be mixed in with your fresh oil as it heats up the next time.