Forget about slug bait let me introduce...beer bait!
Simply, cut the top off an empty fizzy drink bottle, leaving approximately 10cm of plastic from the lid. Make sure the lid is tightly screwed on.
Make a hole next to your lettuces large enough for the whole bottle neck to fit into. The open end of your plastic bottle should sit almost parallel with the soil.
Place three sticks approximately 15cm in height around your plastic bottle in the shape of a teepee.
Fill your bottle up to the halfway mark with beer (slugs aren't fussy about the type of beer, but kids make sure you ask your parents first!).
To ensure that the beer is protected from rain, take the discarded end of your plastic fizzy drink bottle and cut off a section approximately 5cm from the end.
Balance this section on the three sticks you staked earlier. This will create a lid to protect the beer against rain.
Now all you have to do is sit back and wait. Overnight the slugs will slide their way into the beer. And don't just stop with one beer bait bottle, make several and place them around your slug susceptible veges. Believe me you'll be amazed by the results.