With Morrowind, tes3cmd and Wrye Mash installed, I can just highlight all the mods I want cleaned in Mash, right-click and hit the "clean" function and within a blink of an eye, all of my mods will be cleaned in 1 go.

Now it's been years since I messed with modded Oblivion but I remember the process for Oblivion being a little cumbersome...

Run tes4edit
Select none, then select only the ESP to clean
Right-click, apply filter
I remember a window with like a million checkboxes, had to pick the right checkboxes
Right-click ESP, UDR
Wait for countdown to finish before being able to hit Ok button
Right-click again, ITM
Close tes4edit

Back to first step, repeat for all ESPs

(I'm just cleaning the official mods; no user mods)