Mix 1 part flour, granulated sugar and baking soda. Place in shallow dish where mice are most likely to find it. You can sprinkle a little cinnamon sugar, chocolate powder or finely chopped nuts to make it more enticing – just add a bit more baking soda to compensate. What happens is when this hits their stomachs the baking soda forms a gas which rupture their stomachs = dead mice.
You want to do more than just kill them I’m afraid. New ones will just keep coming back. Here’s how we stopped them permanently: https://www.frugalfamilytimes.com/2018/10/how-to-get-rid-of-mice-rodent-proofing.html?m=1
Peppermint oil soaked cotton balls placed around will drive them away.
I tried all the above. Went out and bought poison Tom Kat. Haven't seen a mouse in 9 months. Before that I found, killed 42 in 2 months. They tour down an old warehouse down the road, all of us in neighborhood were infested. Made me very sad and insane because I think they are so cute. After Tom Kat they just went away.