Hot air pen in use

In May 2010, a team of 12 conservators and technicians at The National Archives began a large project to remove pressure-sensitive tape, often referred to as sellotape, from an entire class of records.

The WO 235 class (Second World War crimes case files) was chosen after a survey had indicated that almost a quarter (264) of the files in the class contained pressure-sensitive tape. The tape, applied over 50 years ago, had damaged the files either by degrading and staining or by shrinking and cockling the paper inside.

Conservation treatment

The first stage of the project was to remove the tape carrier. The tape carrier is the strip of acetate that holds the adhesive. Two hot air pens were used to remove this quickly and easily without causing further damage to the paper in the files.

Unfortunately, a tacky adhesive residue was often left on the paper which also had to be removed to prevent the pages of the files from sticking together. This residue was removed using either a solvent (ethyl acetate) or a crepe eraser.

The final stage of the project was to carry out essential minimal repairs to the damaged pages. A number of loose pages which had originally been held in place by the pressure-sensitive tape were reattached by either pasting or sewing.

Project outcomes

At the end of the project in August 2011, all the removed tape which had been kept was found to weigh 5.5 kilos, or 12lbs. From this, it was estimated that three miles of sellotape, the equivalent of 140 rolls, had been removed from over 11,500 of the WO 235 file pages.