Plant some peppermint around them. Mice hate pepermint.
Kill them. A fine melted velveeta cheese stirred with a plastic spoon with Drano Crystals in an Old Can should do the trick.
I would be afraid that my dog would get into this.
I don't know about mice, but I put down cayenne pepper powder, then grate some Irish Spring bar soap on the area and it usually keeps out the squirrels, chipmunks and rabbits from digging and eating my plants. If you use chemicals to kill mice, it may also kill other critters that may land in the area, they aren't the only ones that like cheese. Try the mint, but make sure it doesn't spread and takes out your other plants, it is very invasive. You could also dip toothpicks in real peppermint oil and stick them in the soil and see if that works, renew the oil as necessary to keep the scent fresh and strong.
Since spearmint is in the invasive mint family, watch carefully to make sure that your spider plant roots aren't getting crowded out.