Any got a really dirty coolant reservoir? I mean, you can't even see inside without taking the cap off?? Mine is kinda like that. I took it off and rinsed it out with safety clean and a pressure washer, but it'* still kind of dirty. Any suggestions on how to get it sparkling again?

me and a friend did our engines recently and used sink and basin cleaner..... it comes in a can and foams. spray it on... let it sit.... use a dish sponge with a scrubby side and mines brand new looking....

that cleaner worked for everything in the engine that was dirty

I think the problem was dirt and grunge on the _inside_ of the reservoir...

I cleaned mine by removing it from the car (was doing a flush-and-fill of the cooling system anyway), pouring half a capful of TurtleWax Liquid Car Wash in, filling it about half-full with hot water, and sloshing it around big-time. After some shaking and soaking, it came out spotlessly clean; looked brand new.

I had the same issue....mine has got a nasty greasy film....can't see in it at all
I just added some Super Clean Radiator cleaner...im getting it flushed this week...
for the tank...I already took it out...and had to use Carb Cleaner to get the **** off...it was that bad!!!!!!!!!!

I used brake kleen in mine...I really needed it because my engine oil cooler (in the rad)had a slight leak in it before I changed it. My reservoir was full of oil. Yech