Been running some 'tests' and have discovered that POM collects less dust than PBT. PBT subsequently collects less dust than ABS, which seems to be a magnet for it. Basically I left 3 keyboards out in the same space for 2 days at a time unused, all with black keycaps on them. After 6 days (or 3 tests) the results have been the same in all three cases. ABS is by far the worst for dust collection (best?) as the difference in levels are noticeable compared to POM and ABS. I found especially that backlit caps seem to collect more dust than regular ABS, but that could be a fluke/my imagination.