"Sanding numbers off the monojects
As our slight returns diminish"
Monoject is a brand of syringe, which is presumably being used for shooting up drugs in this case (John Darnielle has referred to We Shall All Be Healed as his "tweaker album", drawn from his experience as an intravenous methamphetamine user*). With their drug supply ("slight returns") diminishing, they seem to be removing the numbers marking the amount of contents in the syringe, presumably so they won't be able to tell how little they are shooting up.
"Sanding numbers off the monojects As our slight returns diminish"
Monoject is a brand of syringe, which is presumably being used for shooting up drugs in this case (John Darnielle has referred to We Shall All Be Healed as his "tweaker album", drawn from his experience as an intravenous methamphetamine user*). With their drug supply ("slight returns") diminishing, they seem to be removing the numbers marking the amount of contents in the syringe, presumably so they won't be able to tell how little they are shooting up.
*See John Darnielle's interview with Marc Maron: http://www.wtfpod.com/podcast/episodes/episode_366_-_john_darnielle