  Large panels of etched plastic, situated aboard the Skylab Space Station and
inside the Ohya quarry near Tokyo, have been used to set limits on fluxes of
cosmogenic particles. These plastic particle track detectors also provide the
best sensitivity for some heavy dark matter that interacts strongly with
nuclei. We revisit prior dark matter bounds from Skylab, and incorporate
geometry-dependent thresholds, a halo velocity distribution, and a complete
accounting of observed through-going particle fluxes. These considerations
reduce the Skylab bound's mass range by a few orders of magnitude. However, a
new analysis of Ohya data covers a portion of the prior Skylab bound, and
excludes dark matter masses up to the Planck mass. Prospects for future etched
plastic dark matter searches are discussed.
