[50mhz] Andrews Heliax assembly?

[G4GED Dave]

Hi
I had no luck at all with this on the "Antennas" Reflector. There are surely 
some experienced Heliax users here...HI?

This is a query to do with the assembly of a connector onto Andrews Heliax
such as LDF4-50A.

When I remove a length of the center polyethylene dielectric with my craft
knife, a thin film is always left stuck to the conductor.

I'm afraid of scraping this away with the knife or using abrasives for fear
of damaging the centre conductor's copper capping/plating.

Does anyone have a sure fire method for cleaning up the conductor properly
in preparation for assembling to a connector please?

Thanks in advance
Dave