Not sure if it's been said, but you want to wash all the plants you have with water and if possible, repot them with organic only soil - even better if you can put big stones (too big for your cham to eat) over the soil in the pots so that he's not tempted to munch on the dirt.
The general consensus here is to NOT feed your cham plants/salads of any kind. While it doesn't necessarily hurt them (see: eating the plants in the cage), it gives them zero benefit nutritionally, and fills their tummy with useless matter instead of nutritious insects. THey're insectivores after all, not omnivores. So to encourage your dude to eat his healthy bugs (dubias, crickets, locusts, silkworms, hornworms, black soldier fly larva (my cham's favorite!), I'd not bother with extra greens for munching.