Rubbing alcohol will kill slugs along with dish soap.
You can put some dish soap in a container along with some rubbing alcohol and then put the slugs in the container and within a day or 2 the slug will eventually die.
You can also get rid of slugs and kill slugs by pouring salt over their body and the salt will cause the slug to dehydrate and then die eventually.
The salt on slugs kill the slug much faster than the rubbing alcohol and soap and you don't have to touch them to put them into the container.
Or you can put catch and release traps to use to get the slugs and then release them somewhere else.
I just put some salt on the slugs when they are in my yard and I don't want them and the salt kills the slug within a day and sometimes sooner.