It looks like the only way they mention on how they isolated these chips was with a magnet.
Exactamondo! Reading the paper
2. Chip Size, Isolation, and Examination
For clarification, the dust samples collected and sent to the authors by Ms. Janette MacKinlay will be sample 1; the sample collected by Mr. Frank Delassio, or the Delassio/ Breidenbach sample, will be sample 2; the sample collected by Mr. Jody Intermont will be sample 3; and the sample collected by Mr. Stephen White will be sample 4. The red/gray chips are attracted by a magnet, which facilitates collection and separation of the chips from the bulk of the dust. A small permanent magnet in its own plastic bag was used to attract and collect the chips from dust samples. The chips are typically small but readily discernible by eye due to their distinctive color. They are of variable size with major dimensions of roughly 0.2 to 3 mm. Thicknesses vary from roughly 10 to 100 microns for each layer (red and gray). Samples of WTC dust from these and other collectors have been sent directly from collectors to various scientists (including some not on this research team) who have also found such red/gray chips in the dust from the World Trade Center destruction.
Note the word "isolation".
And that is all they did. There is no mention in the paper of finding chips that were paint, nor is there any mention of the method used to isolate thermite chips from paint chips. Funny how Millette uses the exact same method, finds red/gray chips with the same EDS spectrum for both layers, but concludes the material is paint with no thermite in sight.
It always amazes me that truthers can be so dishonest and wilfully blind when the facts are printed in black and white in a paper they champion, staring them in the face.
MM - please quote the relevant part in the Harrit et al paper where they discuss the method of isolating thermite chips from paint chips.
(I think he still has me on ignore btw)