Little Greek Words and Long Roads into the OT

Last week I led children's work on Mark 7:1-23 and this week I'm leading homegroup on Mark 7:24-37, preached last Sunday (see last two posts).
Having written the last post, I've looked at the Greek for the passages last week and this. Aaargh!
If you have a resource like that, use it - it is worse that Amateurish to do otherwise.
In 7:1-23, the koinoo word group is used for defiled or unclean, meaning basically "common". In 7:25, the spirit is akathartos, "uncleansed". Something that is akathartos renders things holy and common equally akathartos.
What does that mean for the reading that 7:24-30 presents a solution for 7:1-23? I don't think it raises a problem, but some scepticism is required. Firstly, the word akathartos describes all spirits in Mark. Secondly, we're entering a new section in the Gospel, a journey outside Jewish territory.
Equally, the fact we leave Jewish territory, Jesus having just abolished the food laws and redefined uncleanness can't be coincidental.
I think the point is that we are not fit for God's presence. The drumbeat of Leviticus is "Be holy" (qds word group); it isn't "be common" (a call the Amateur's snobby side would find hard.) But we are always outside of the holy by virtue of our hearts. Jesus however is well-equipped to deal with the root cause of our not being holy, as He demonstrates by driving out the demon.
And the last post? What about the moral and forensic nature of uncleanness. He might be able to deal with the cause, but can He deal with the consequence, namely our lack of holiness and our guilt before God? I refer you to the solution discussed there.
By the way - have you noticed how Jesus helps the helpless? He deals with people with thoroughly broken bodies or under terrible spiritual oppression. Isn't that because we're all in that boat because of the state of our hearts: helpless and oppressed?