Firstly, remove the power supply from the 6100 and pull out the useless air filter. Useless because it's actually facing the wrong way to keep dust out, it keeps dust in. :?: :?: All it does is end up clogged with gunk and impeding proper airflow.
Secondly, check and if necessary (which it almost certainly will be) wipe and replace the heat transfer paste between the 601 CPU and heatsink. Ditto the G3 if you can work out how to dismantle it safely. The 601 heatsink clips through the motherboard at the corners IIRC.
Thirdly, place a barrier under the 6100 to physically separate the incoming cool air from the outgoing hot air. I used a folded dishcloth diagonally from the front right foot to the left rear foot.
Secondly, check and if necessary (which it almost certainly will be) wipe and replace the heat transfer paste between the 601 CPU and heatsink. Ditto the G3 if you can work out how to dismantle it safely. The 601 heatsink clips through the motherboard at the corners IIRC.
Thirdly, place a barrier under the 6100 to physically separate the incoming cool air from the outgoing hot air. I used a folded dishcloth diagonally from the front right foot to the left rear foot.