smokelessly

“The figure on the tapestry smoldered, burning slowly and smokelessly.”

Fictionaut: Virginity

“It is safe to say, however, that no plant will operate smokelessly under any and all conditions of service, nor is there a plant in which the degree of smokelessness does not depend largely upon the intelligence of the operating force.”

Steam, Its Generation and Use

“With those words the swarm of torii floated a few feet before the Boss and dropped a small glove made of human skin and it burst into flame and disappeared smokelessly -- an ultimate sign of Afterlife loyalty for the Living Computer.”

Editorials from Hell's leading daily newspaper

“Because it’s largely pure carbon, charcoal burns mostly smokelessly at temperatures approaching 1,800°F/1,000°C.”

Simon & Schuster: On Food and Cooking, The Science and Lore of the Kitchen