refine - verb

• improve or perfect by pruning or polishing
• make more complex, intricate, or richer
• treat or prepare so as to put in a usable condition
• reduce to a fine, unmixed, or pure state; separate from extraneous matter or cleanse from impurities
• attenuate or reduce in vigor, strength, or validity by polishing or purifying
• make more precise or increase the discriminatory powers of

refine - thesaurus

complicate   down   elaborate   polish   rarify   rectify