Do you have a reference for that?
As I posted earlier clean in cricket means without touching the ground but possibly with juggling.
We know early law makers read the cricket laws as they refer to a cricket catch in the knock on law.
Camquin
No, I don't have a reference for that, though
"direct" is well understood from the touch Law Definitions
[LAWS]‘Kicked directly into touch’ means that the ball was kicked into touch without
landing on the playing area, and without touching a player or the referee.[/LAWS]
So if "direct" also means the same thing in the Mark Law, what does "clean" mean? Why use the word "clean"?
In my playing and refereeing days, you had to have both feed planted to take a Mark and if you juggled the ball, no mark would be awarded. By 1996, that changed to one foot
LAW 16. FAIR-CATCH
(a) A player makes a fair-catch when in his twenty-two meters area or in his Ingoal
he, having at least one foot on the ground, cleanly catches the ball direct
from a kick by one of his opponents and, at the same time, he exclaims
"Mark!"
(b) A free kick is awarded for a fair-catch.