Just stop all nutrients/fertilizers/supplements for the last 10-14 days before harvest and give only plain water in normal amounts and at normal intervals and let the plant "flush" itself naturally.
This is all that is needed.
There is no need to "flush" the pots with gallons of water, this does nothing.........except cause over saturated flowers that then can become prone to mould when drying.
Over the last forty years I have tried many, many "techniques" for pre-harvest treatments , including "rinsing the pot", not stopping fertilizers and all sorts of products put out by the various fertilizers companies.
Pot rinsing just causes hyper plumped up with water buds that then are hard to dry.
No treatment at all and fertilizers right to the end...this causes funny/awful taste and poor combustion.
Multitude of commercial products designed to clean your buds.........all are a waste of money.
Stopping fertilizers and giving only plain water for the last 10-14 days........this produces the best results when it comes to consumption and the drying process.
Also, in my opinion, dry trimming is better than wet trimming........the flowers dry better with the leaves left on.