2005 Kia Optima. I made myself a 'flush adapter' out of Home Depot parts
The fluid in the reservoir was the amber color of motor oil, but I remember that it was nearly colorless when I last changed it. So I decided it needed changing ASAP.
Disconnected the return line, and found a brass PEX adapter at Home Depot that fit the return line on one side, and a reasonably-sized vinyl tube on the other.
Silicone'd the tube to the fitting, and stuck the other end in the return line. It fits tight enough not to need a clamp. Stuck the vinyl into an old milk jug.
Got the car up on jackstands. Pulled the fuel injector and ignition fuses. Turned the wheel back and forth while cranking to get a flow going. Once I got the fluid moving, all I had to do was turn the wheel back and forth and that pumped the fluid at a nice pace; I'm not sure if I even needed to crank it at all. I had the wife add fluid to the reservoir to keep it topped off.
Flushed through a quart and a half; it started running clean at 3/4ths of a quart but I wanted to make sure I had as much old out as possible.
All I could find was AuzoZone or Prestone brand fluid. Last time I used Castrol or Valvoline Synthetic (can't remember which) but nobody has much choice in PS fluid around here. Neither the AZ or Prestone mentioned any specs on the back and the markings on the bottles were identical (except that one bottle was black, the other yellow), so I went with the cheaper AutoZone fluid.
Next time I'll plan farther in advance and get some synthetic. With my home-made adapter it's an easy enough job to do so I might do it soon.