For my interiors, I usually
1) check everything out first to see if there's candy, gunk, stains, wetness, garbage, loose change/receipts/jewelry etc (always placed in the center console area so my customers know im trustworthy!)... throw out any garbage in car like wrappers etc...
2) vacuum, + brush carpets if needed, incl trunk
3) extract floor mats and lay out to dry in the sun (if rubber, i usually wait til when im cleaning door jambs to clean them w/ apc) > extract seats if cloth, starting with the drivers seat, treating spots first w/ folex, and scrubbing....spraying folex on entire seat and using warm water only in my LGM to extract.... usually doing passenger seat next, then rear seats ... do the same thing with floor mat of each respective seat after doing seats, or, if seats are leather, do the same thing with floor mats only, and then clean leather. extract trunk if material is carpet, otherwise a trunk vaccuum suffices if its made from that odd compact, black, plastic gunk found in most cars...sometimes if there are bad stains i will extract/spot treat, but i generally just vacuum/brush the trunk if its that plasticy stuff.
4) spot treat headliner w/ steam/folex/both
4) clean dash, center console, steering wheel, vents, etc....ive typically used folex for all of this (its relatively inexpensive in comparison to other cleaners and it seems to work well for all but the toughest/greasiest stains....i started using megs apc (green one) but i just used it in my 97 accord and it made my window switch cluster and handle surround chalky!!...so i will prob be going back to folex...and experimenting w/ my steam cleaner too... as ive been displeased w/ its performance thus far except for glass/door jambs...
5) clean kickplates, handles, interior of b pillar, plastic heating/cooling vents under seats, seatbelt latches (scrubbing inside the "press" engraving w/ a toothbrush, any other plastic/vinyl parts in interior
6) clean door panels and window seams ( i usually leave windows open starting at beginning of detail, to help seats dry...yes sometimes debris gets in the car (pollen etc) but i always do a 2nd vaccuum anyway... (pollen/debris to be vaccumed is better than wet seats)
6)clean door jambs, rubber door seals etc...sometimes steaming w/ apc and towels, sometimes laying a big, old beach towel down and using the mist setting of the hose w/ apc and various small brushes and letting cleaner sit if needed (this method, while precarious b/c u have to be careful about not getting the interior wet, is usually much faster....just like how washing the exterior of a car is generally faster than using rinseless/waterless wash). also, i usually use big old towel to dry door jambs when doing it this way... its cheaper and easier than using a bunch of my small terry towels up and i usually get away w/ using 1/2 big towels to dry.
7) lightly clean engine w/ same method(s) listed in step 6.... making sure to clean not only the engine part, but the inside of hood, engine jambs etc.. (i usually dont perform a full engine detail...i have that listed as an extra fee b/c my time is usually already tight....i usually then, clean the trunk jamb too.
7) apply dressing to interior plastic/vinyl surfaces and rubber seals.
8) apply leather conditioner as needed, in addition to, or in replacement of step 7.
9) I wait until after the exterior detail to clean glass, so for the sake of things being in order im listing exterior steps too all in step 9 with ">'s" to separate steps.... (wash (rinseless/waterless/traditional 2 bucket...washing car 1st then wheels, chrome exhausts etc then wheel wells...have yet to try gary dean method)...>squeegee + towel dry>air dry>clay>tape trim>correct headlights if paid for/if needed and im feeling generous and have enough supplies
> compound>polish>wax/seal>remove tape and apply exterior dressing(s) on trim/tires> wax/seal wheels)
10) roll up windows partly, then steam edge of glass
11) roll up windows all the way, then steam interior glass using 3 terry cloth rags...1 to spread steam and really clean the glass as SOON as i finish steaming window, one to wipe in opposing directions (up/dwn then left/right), and one to buff lightly to ensure no streaking....if i dont have 3 terrys on hand i use 2 MFs for 1st two rags and terry to buff b/c of it's "bite". (sometimes the rags get wet so ill replace each as i go along)
12) repeat with exterior glass
13) polish exterior glass if needed or if i have time (have only had to do this a few times and wasnt overly impressed w/ DP glass restorer...)
14) apply rain-x to exterior glass and wiper blades following directions on bottle if asked/if i have time
15) Revaccum interior and check over results.
sometimes i get distracted and i do steps in a different order if i forget to do something, but that's basically my method.
