Here's a safe approach to getting rid of roaches. Get yourself an empty glass jar. A washed out mayo jar will do. Dump your used coffee grounds into the jar; at least, enough to cover the bottom. Put the jar outside. You'll need to sit the jar on the ground and tip it at a slight angle to lean against a wall or something. Don't throw the lid away.
The roaches will not be able to resist the coffee's aroma. They'll climb up the wall and down into the jar to get to the grounds. Because the glass is slippery, they won't be able to get out. If there are any roaches around, it won't take long before you find your jar filling up. Get your gloves, put the lid on tight and toss the whole thing.
Just be sure you use your jar outside. You don't want to lure the creepy crawlers into your house to get rid of them. Oh, a couple of spoons of wet instant coffee will work just as well.
Tip from Kathy, presumably a user on www.lifehacker.com