OK I think I've got the same problem as you, We bought this couch used, and apparently it sat outside for a while before we got it. So now its been 3 days and I've killed 3 earwigs... No horror movies for me till I'm sure I got this cleaned up.
So far I've heard fantastic spray (the countertop cleaner) will kill them on contact. But can be expensive. And soapy water will kill them too, but this will attract them as well. So you set out a little saucer with soapy water in it, they are attracted to the smell of the soap, and drown/die in the saucer. One other is to roll up a few sheets of newspaper into a crumpled tube,. And moisten it, they love tight squeezes and damp places so you leave that under the couch overnight, and then in the morning, its supposed to be filled with them. Then you just toss them.
Personally id rather them dead then trapped in paper, so I'm going to use the soap method, and then get some roach motels.
Hope it works for you and for me.