We are going to omit the bad particles leading off class #13.

Instead of viewing the member particles using Montage from doc. file, use Categorize->Doc. file montage.

Name the output file firstgoodparticle.

The starting key number should be the class-number.

Select the first good particle.

If you decide to use this method, you must pick the first good particle for each good class in that reference-view. Thus, to keep all the particles, you would click on the first one.