Adjectives

(s)cleanlyhabitually clean“cleanly in their persons and habitations”

Adverbs

(r)flawlessly, cleanlysmoothly and without difficulty; precisely and deftly“the gymnast landed flawlessly”, “she played the piano accompaniment cleanly”, “he bounced it cleanly off the wall”
(r)cleanlyin a manner that minimizes dirt and pollution“the motor burns cleanly”