How to prevent earwigs in guinea pig cage?

If the cage is directly on the ground try putting the cage on a sheet of plastic so that there is a barrier between the cage and the grass.
Not sure if that is a good idea but its all i can think of.

When I used to get earwigs in my basement I would roll up newspaper and wet it a bit. This drew the earwigs in and then I would have to just simply toss the newspaper. I would recommend setting up one of these traps near your guinea pig cage as well as where you believe the ear wigs are getting into the house from.

Earwigs like cool, moist places and also are attracted to food sources such as would be found in a Guinea Pig cage. Veggies, lettuces, carrots, etc. You may need to find a way to elevate the cage on a table for awhile to deter them. Obviously, being a Guinea Pig owner you are hopefully aware of their high veggie needs and any uneaten and wilted foods need to be removed within a few hours at most.

It’s a double story cage that is mainly on the grass. It’s covered with a plastic tarp when it rains or brought under shelter. Such an annoying situation as can’t put any chemicals in there!

@jlk2525 Right…no poisons. You can take a length of cut garden hose and put that nearby, they will go in there to hide and then you can shake it out somewhere else or squish them. haha

Put the cage up on bricks, and make sure the grass is short all around and under the cage. That would help, for sure.

Going to try the hose idea! @Coloma