Also, if the TV's built-in degaussing circuit is unable to clear it an engineer can manually degauss the TV's shadowmask with a portable electromagnet designed for the purpose.
For that you shouldn't be charged much for the job, as it takes all of 10 seconds to do.
The worst scenario is..a very powerful magnet could in theory warp the shadow mask which would require a new cathode ray tube.
Most likely it will disappear with normal use.
Cobweb
October 2005