I don't know about feeding the lawn but if you put some jars with beer in around the garden you can catch a lot of slugs!

Beer is high in sugar and (very) low in nutrients so it would just make a sticky mess of the lawn, and possibly kill the grass. Being a beer drinker, in moderation of course, I wonder why you don't give it away to friends.

I'm thinking steak and ale pies, beef casseroles, etc etc...

Thanks to all for your replies but the good stuff is already gone, this is the dregs in the bottom if the barrel!!!!!!!! Friends already inebriated!!!!!

Slug traps then