People have been deveining shrimp for years without the handy deveiner tool, which can look like a vegetable peeler with only half of the metal blade (like this Good Grips Shrimp Deveiner from OXO ...

simply make a shallow cut along the back of the shrimp and remove the dark vein with the tip of a knife or a deveining tool. For smaller shrimp, deveining can be skipped to save time. If you're ...