I have used Renaissance on my K38 and it made a transformational improvement. I've also used it on some of my stainless weapons to remove some baked on stains.

Apply a very small amount and polish off with a clean cloth... and later buff for a high luster.

After the guns, I used it on my USMC officer's sword with great results as well.

Finally (HERE'S THE DOWNSIDE TO THE STUFF)... My wife was so impressed that she got me to polish the brass banister on the stairs with it. The brass had tarnished but came out like new... a lot of elbow grease on this project. The good news is that it's left protection that has lasted for eight months now.