[s-cars] NAC Oil Cooler Flush

[mtgadbois at aol.com]

Gentlemen:

I picked up a used auxillary oil cooler and lines for a non-Audi car.  
Before I install it I want to make sure it is perfectly free of 
anything nasty.  I thought of running a flush through it both ways and 
catching the fluid in an oil pan and looking at it on a nice sunny day 
- all the better to see suspended metal flakes.  So what fluid should I 
use.  Oil I thought would be thick.  Maybe brake fluid is better or 
kerosene?  Any BTDT?
Thanks,
Mark near Chicago