This Instructable tells you how to make a beer-baited slug trap from two empty drinking water bottles. It introduces no harmful chemicals into the garden and does not harm the local wildlife (apart from the slugs). It also re-purposes items which would normally have been thrown away. Using green bottles makes it merge well into the foliage. Altogether, a green idea.
The first one was made in the space of 5 minutes. I have had slugs eating my plants and a work colleague mentioned the same thing just as I was pouring fizzy water from a bottle. It was one of those 'eureka' moments. I had several of the bottles in my cupboard which would 'come in handy one day' and that was the day! 5 minutes later using only office equipment I had the first slug trap built.
The photos show the sequence of making the slug trap, and at the end are some pictures of the garden looking its best.