Transferring From A Password Protected Document ?

[Robert4]

Hello,
Running Mojave.

I have a Password protected document.
I open it up, and do the Control-Alt-4 bit to select a portion of it. Or, perhaps I do a full COPY.

I then paste it in another password protected document.

Fine, no problems.

How can I be sure that what I copied is not residing, totally unprotected in some Mac Clipboard I (might)
have, or anywhere else being "saved" automatically ?

Where should I check ?
How to totally prevent ?

Thanks,
Bob

 

[Fishrrman]

After you do the copy/paste from the password protected document...

... copy SOMETHING ELSE to the clipboard to "clean it out". Anything at all will do.