How do you "clean" out your engine?

My Grandpa let me borrow his pickup one time, he drove like a Grandpa, the first time I stepped on it I thought I broke something, Black smoke, chugging, sputtering. After driving it for a few hours, I could burn the tires from a stand still, (350 Cheve 2wheel drive long box, ugly brown/white two tone). I returned it to him and he asked me if I fixed something cause it runs better. I just told him that running it down the highway cleaned it out a little, I didn't tell him that it would now burn the tires from a stand still, no brake. Morall of the story is, engines are built today to be driven in the higher RPM's, don't be afraid to get into them once and awhile. But if you insist on "babying" it, getting into it every now and then will definetley help. Don't know if I needed to say all that, just brought back memories.

When driving my '02 (it's not a daily driver, so it sometimes sits for days between uses), I drive her "reasonably" until she warms up.

But I've definitely noticed that after some post-warm-up, high-rpm wringing out, she seems much "happier" and the exhaust tone gets to where it should be.