You shouldn't have to make excuses in your own house. You can just say "well, i'm gonna kick you out for today" without giving an explanation. There's nothing impolite about that (unless it would be people you invited and you kick them out after five minutes lol)
That's what i say (not that i have many guests in the last years, i just dont let anyone in hahah)
just say it, without excusing yourself as if you would need to in your own house. It might take some practice and get you some cultural goosebumps if you have been "trained" to be "polite" (polite usually means lying, have you ever noticed that ? parents tell their children not to lie BUT to be polite, but if you have to be 'polite' more often than not it comes down to lying, or masquing ...)
But when you can do it without getting your solar plexus in a knot in the end you'll respect yourself more and believe it or not people will respect you more too.
No need to get angry or tell lies, jus say "I'm going to kick you out now for today" or "Id like you to leave now for today" or simply "Id like you to leave now"
with no "because" attached
in your own house