...
Its the function org.apache.coyote.http11.Http11Processor.prepareRequest() which is responsible to convert a received request to such a format, that it can be further processed by Tomcat's internal engine.
You need only to instrument this function so, that the header is accessed and removed at the end of the method:
...
.
The headers are stored in the variable "headers". Its class provides the functions to access and remove:
headers.getValue("InspectITID"); // To access the ID
headers.removeHeader("InspectITID"); // To remove the header
}