Ask MeCha: are slugs harmful?→[More:]So I live in a Victorian house, and its cellar has been converted into an office, and has been 'dry-lined' (I think that's what it's called - the previous owners left details of what's been done). I work in the basement, which is generally pretty awesome, especially in hot weather.

Recently I've noticed slug trails on the rug in the basement in the mornings - sometimes new ones appear, probably 2-3 times per week. I've never yet seen a slug down here.

My question is: should I be trying to get rid of them? I can't even work out how they're getting in - there's a ventilation shaft from the garden, and a hatch through to the other half of the cellar which is full of hard-core and not dry-lined, and a small gap to the outside next to the stairs down to the cellar.

They're not causing me any inconvenience apart from a slight 'ewww' factor - could they be causing damage I don't know about?