Hate to tell you this, but I find very little actually gets rid of them all. When I freeze any veggie I prepare it first by soaking in salted water for about an hour, then I drop into boiling water for 2 minutes, then back into ice cold water to chill quickly. Then I pack and freeze.
However, I find even after I have soaked in salted water , when I go to tip the boiling water out of the cooking pot after blanching, I have to scim off the dead floating caterpillars that were still hiding in the broccoli when it went into the pot.
The salted water may have stunned or killed them but many still in the brocolli and not visible when they went in the pot.
I suspect we eat a lot more than we think
Sorry
XX Jeannine