Never had the need to wash off dirt ^^
But I water cure, if I had the bad luck of mold in a curing jar (hasn't happened since i ozonize my jars before use) or the weed is potent but tastes like old socks () .
(Who doesn't knows water curing: Need a big glass jar with lid to hold your weed and a fine mesh and weight to put on top (just enough to keep all submerged). The only rule you must follow, everything must!! be submerged, no weed can be above the water line or have contact with air. Rest is simple. Put the weed in, fill up very gently the jar with sterile water (i use carbon filtered and UV treated, E-Spring), put mesh and weight on top. Put it in a dark spot around 18C degrees. Change the water depending on color, first 2 days most likely 2 changes, next 3 days one.. after 5 days the water should be more or less as clear as what you filled in, if not, go on till it is. Osmotic transfer is over and your buds are done and cured. Dry as usual (stick snap).. no need to cure anymore.. when dry, is smokeable)
The smoke will turn out extremely smooth, and i mean very very smooth.. what is the good side.. but also extremely tasteless! as with the nitrates, sugars and other nutrition, washes terpines out too. I actually try to avoid any kind of wetting the colas during the last 4 weeks (yes they get a rain cover if needed ^^). Even the trichomes resin is lipophylic (likes to combine with fat), still washes with the water, as breaks off very easy. Not sure I would do anything to a bud, if no action is needed. So washing just because you can.. I wouldn't do. If you have muddy buds keep em out of the mud.
And for sticky fingers while harvesting.. a single drop of olive oil and cleaning your fingers or gear becomes very easy.. plus.. still can eat it ^^ wouldn't smoke it