If they're older matches (particularly if they are front-strikers) I keep the match sticks in the book. Otherwise, remove carefully, staple first.

Of course, if they are Feature Matches or have printed sticks, I'd recommend keeping the matches in as that's where at least half the interest in the matchbook is.

I don't collect the toiletries from casino hotels, but have been known to bring them home to use (particularly if they smell nice ). I usually have my own liquids that I bring along on the trip in a zip-lock bag, so if I take any hotel stuff home with me, they go in the same bag. Never had a leak create a mess but it's always possible.