I remember when I was little I'd get my little brother carry a box around as I filled it with slugs. Just went around picking them up. Hundreds of slugs, if not thousands every week or two. One time though I filled one of those paper boxes that hold reams of paper half full with slugs climbing over each other... and then for air decided to poke holes in the side of the box... with a pencil. Let's just say the next morning my mom freaked out and she was using a long stick to pick off hundreds if not thousands of slugs off the side of the house, the windows, light fixtures and the doors... everywhere. She was glad we didn't bring the box inside. LOL The whole front porch area glistened in slug slime. HAHAHA
We have these banana slugs that are like 8 inches long when they are moving and shrink up to the size of a large kiwi when you poke them with a stick.
The only thing that has managed to keep the slugs under control has been the 10 years of free ranging the chickens. They don't eat adult slugs, but do eat baby ones and their eggs. Of course, they are fenced out of the gardens though, since else I'd have no garden.
Sorry this post was no help, had to share my slug story.