Toroid choke adventure

Snap on Choke

A few weeks ago I was on my radio and once again I experienced some RFI issues with my PC and my morse code key. On my PC the mouse was moving all over the screen and the morse code key when using it I had extra dots and dits being sent. I use snap on chokes but I have seen in the past the chokes have become unsnapped and the choke is not able to do its job 100%. After my mouse and morse code key issues I move my radio desk out to look behind and have a look at the installed chokes. I was not surprised to see a number of chokes that were unsnapped. It was time for me to take this issue head on and solve it once and for all. I decided to put toroid chokes on each end of each

Not sure if this is normal

cable. I also decided to wrap each snap on toroid chock with zip-ties, I re-wound each toroid nice and tight and added the zip-ties to secure them. I am happy to say it has solved my RFI issue for over 3 weeks. I did have a question, I did notice on a few of my snap on chokes the cores had some markings on them. I am not sure if this is normal or if there was an issue with the cores?