I would like to open my earlier question up to see if anyone else can help to clarify.
There is a quote from Sayagi U Ba Khin in Jack Kornfields book "Living Buddhist Masters - "with the awareness of the truth of anicca and or dukkha and or anatta.he develops in him what we may call the sparkling illumination of nibbana dhatu a power that dispels all impurities or poisons -the product of bad actions,which are the sources of his physical and mental ills.In the same way as fuel is burnt away by ignition,the negative forces[imputities or poisons]within are eliminated by nibbana dhatu which he generates with the true awareness of anicca in the course of meditation.the process of elimination should go until such time as both the mind and body are completely cleansed of such impurities or poisons." Jack Kornfield refers to nibbana dhatu as the "agent or mode of purification" does this all fit in with how Goenkaji teaches? Would penetrative insight a be substitute term we could use for nibbana dhatu or is nibbana dhatu something more from the perspective of your tradition? Is nibbana dhatu the same as a light nimitta.
I also believe that there is some kind of view about purity of energy within the tradition, which would explain the reluctance to share meditation facilities or to sit/practice with those from other traditions within the Theravada, is this correct? If it is so do you think it ij just a cultural thing, which has come out of Myanmar with the practice or is there more to it?