McKee's 360 Has a pink color and provides an EXTREMELY robust sealant. It is stronger than some dedicated paint sealants out there!
Like Mike Phillips says
"If Its easy to remove the wax/sealant from your pad then its easy to remove the protection from your paint"
No pad cleaner is going to remove 360, It is not a "stain" It is the sealant.
However If you use a AIO on 1 pad that pad should now be a designated AIO pad due to the wax/sealant content that is in that pad. Any Quality AIO that you use on your pad the sealant/wax will linger in the pad no matter what color it is. It just might not be visible to the eye.
The "stain" is not going to alter polishing performance whats so ever. Like I said above if you used any AIO for that matter it is wise to dedicate that pad as a AIO pad. If you are doing a multi-step correction its not wise to use that pad due to the wax/sealant that it provides.
when you get a chance read this article I wrote on cleaning pad:
https://www.autogeekonline.net/foru...-mckee-s-37-polishing-pad-cleaner-review.html
Do not go to extreme measures to remove that "stain" as you will only be degrading the life span of that pad.