A Jain household will try to stop mice in a way that protects both:

• their own health and cleanliness
• the life of the mice (ahimsa – non‑violence)

Because you mentioned “undetectable cracks and holes”, the focus should be on strong prevention and humane (non‑killing) control.

1. Make the house unattractive to mice (first and most important)

• Keep all food in closed containers (metal or thick plastic boxes with tight lids).
• Do not leave food or crumbs out at night – clean the kitchen floor, counters, dining table before sleeping.
• Cover dustbins properly and empty them regularly.
• Store grains, flour, nuts, etc. in sealed containers, not open bags.

If there is no easy food, mice are less likely to enter or stay.

2. Block entry as carefully as possible

Even if cracks are “undetectable”, you can still:

• Check around pipes, drains, under sinks, behind gas/electric lines, along skirting/trim, and fill any visible gap with:

- steel wool + filler, or - metal mesh + sealant

• Fix torn window nets, gaps below doors (using door sweeps/brush strips), and broken ventilator grills.
• Keep storage areas tidy so you can see droppings or signs of mice early.

This is prevention, not killing, so it fully supports Jain principles.

3. Use non‑lethal methods if mice are already coming

• Use live / humane traps (cage‑type or box‑type that do not injure):

- Put a little food (peanut, grain, etc.) as bait. - Check traps frequently so the mouse does not suffer for long. - Release the mouse far enough outside (e.g., in a safe open/green area) so it is unlikely to return.

• Avoid:

- Poison - Snap traps - Glue boards All of these cause clear himsa and are against the spirit of ahimsa.

4. Gentle repellents (where acceptable)

Some households also try natural repellents that only discourage, not kill, such as strong smells (peppermint oil–soaked cotton, etc.) placed where mice enter. If you use anything like this, ensure it is not directly harmful or burning the animal.

5. Spiritual attitude

• Accept that complete zero‑hinsa in household life is very difficult, but we must minimize harm.
• If despite all care, some himsa happens unknowingly, Jains usually:

- feel inner regret (prayaschit), - remember and recite “Micchāmi Dukkaḍaṃ” and similar kshamāpana, - and try to improve their carefulness (apramatta) going forward.

So, in summary: A Jain household would not use poison or killing traps. They would focus on cleanliness, sealing gaps as far as possible, storing food securely, using humane traps, and releasing mice outside, all with a mindset of compassion and carefulness.