Not to knock the advice given here by some of the elder bees because it is good sound advice that works.
The only problem Swim sees with doing an "e-gull" tetra wash on the GUPS prior to doing the ahgreich method is that only 3-5 boxes will fit in each coffee filter at a time.
You would have to essentially line up a bunch of jars with a filter in each.
Add 3-5 boxes in a dish pour in tetra swirl for 60-90 seconds and then pour it through the jars with filters, wring each one out individually and then scoop the pill mass back into a coffee pot, beaker (whatever one decides to use) and then FINALLY begin to proceed with the extraction.
Unnecessarily labor intensive and time consuming, not to mention the space required to do all this. Then again, waiting for what little that sticks to each filter (waiting for it to bee dried before it ALL can bee removed)
Swim is an advocate of the e-gull and has used it since wareami unleashed the beast.
But why go through all that labor, mess and time, when you can just evaporate the toluene down to a skin, allow to cool and then just pour off the gakk?
It is ALL inclusive, pros outweigh the cons.
After doing this, in all actuality, washing the freebase with water in the end is not even necessary if all gakk tainted solvent is poured/dripped (decanted) off.
Then as was just mentioned for ultimate speed and efficiency, instead of fresh toluene and water added and then titrating with muriatic to get pseudo HCl, one can just add fresh xylene and gas.
If Swim wanted to do washes, boils or pre-soaks, he would have stuck to pills containing povidone.