Make "Sign Out" really Sign Out

Because of some "issues", I have had occasion to switch from one Netgear Community Profile to another.  However, when I use the drop down menu to "Sign Out" and then click on the button to "Sign In" again, instead of getting a prompt for user credentials, I am automatically signed into the previous profile.

My workaround is to open a separate browser and "Clear Browing History" after signing out.

Yes, it is really convenient to have web browsers remember user credentials so that they can open a web site and be signed in automatically.  But that should be a user choice.  i.e. if I close the web browser without signing out, then the next time I open the web browser and key in that site, it is OK to sign me in automatically.  However, when I deliberately SIGN OUT, that should erase whatever cookies are being used to remember me.