I have actually thought about flushing the MG soil several times prior to use. Never got around to actually trying it though. I just figured itd release most of the nutes before I actually used it. I always figure, no matter what you are using, if it works for you then keep doing it. If it isnt broke dont fix it haha. I have learned that there are alot worse types of soil out there than MG. Hyponex for example is horrible. As for jahoo, moving them like that is fine just keep a really close eye out for bugs. Its easy to contaminate a grow room doing that.