For eg: This is one text frame
Go to Object>>Flattern Transparency (DO NOT Convert All Text to Outlines).
It will return all text in different frames :
Then Object >> Clipping mask >> Release followed by Select >> Object >> Text Objects and CTRL+X - Cut
So it will leave behind all clipping boxes, Select and delete all boxes.
CTRL+V (paste) all text frames from Clipboard.
Hope this helps!