I'm kind of hit or miss with full cleanings, until I start having issues with tanks leaking or gurgling, I've found that this can be caused by poor air seals, so I'll disassemble the entire tank and soak it in hydrogen peroxide for fifteen minutes to a half hour, then scrub it all down (especially connections between the different parts) with a swab. It's kind of amazing what you can get off seemingly clean parts. This usual resolves any leakage issues I was having.
I've also found that I can resurect many coils by running them under extremely hot water, soaking them in hydrogen peroxide for a few hours, rinsing them again. I then take a small piece of toilet paper, roll a corner to a tight point and work it down both openings, pulling out quite a bit of crude off the coils themselves. I never had much luck with dry burning coils. It usually ended up burning them out completely.