Is there an effective way to do this without removing a ton of stuff? AC works great but air flow is not what it once was. I have no filter and 300k miles may have left some nasty on the coil. Probably just a glutton for punishment.

I had good results using coil cleaner designed for home a/c sprayed through the air intake behind the wipers with the a/c off, fan on high, and not on recirculate. I want to say I used half the can, let it sit for 30 mins and the. Used the other half. It will make the cab a little stinky, but it cleared up after a week or so.

I used one that came with a fitting that you installed in your evap case (under the dash) after you drilled a hole in it. You had to be careful not to drill into the evaporator. I think I got it off of ebay.

This one doesn't require drilling but I'm not sure how you could make sure you got it to the top of the evaporator.

It did a decent job on my 2000 Ram and I wasn't the only one that noticed a difference.

Buy the toyota evap cleaner.