Some things I find interesting.
 Hope you also do....

 
Dummy Testing Coils with Red Defacement Lines

Shown below is an additional example of red defacement lines on tagged Cottrell press FTPO coils.  Longer strips, 12 or more stamps, would be needed to show a complete revolution of a usually sized Cottrell mat... if these defacement lines were indeed actually applied on the Cottrell press. 

It is still unknown if these defacement lines were added by BEP, the USPS or others.

This strip has three red defacement lines and also has vertical lines about every three and a half stamps.  Between the horizontal lines are other markings one of which can be deciphered as an inverted "DL". 

 
 
Shown at 150%, the full strip of eight more easily shows the repeating nature of the defacement pattern.

 
 
This is only an initial attempt to document for collectors the different defacement lines which can be found on the Cottrell press tagged FTPO coils.  This is NOT meant to be an exhaustive catalog of what exists.

Surely, other types of defacement lines must exist in other collections. 

If you know of, or have examples of others,  I would appreciate the information and will gladly post scans of your coils giving you full credit.

Hope to hear from you