Derogatory slang name for Tasco optics, reflecting their general reputation for cheap and/or poor quality products, specifically with optics for firearms.
Also used as a general term for a cheap/low quality riflescope.
"I went out to test fire the used rifle I bought. It came with a Trashco scope, so it will probably shoot better once I put a real scope on it."
"Dude, you spent all the money on the gun, but put a trashco scope on it?"
"It's just a .22 rimfire. A Trashco will work find on a gun like that."