Note that these precautions are intentionally extreme. In part, because there are (still) so many unknowns; in part, because nobody is perfect, and extremity leaves room for error and compromise. Following them perfectly should reasonably avoid COVID-19 (though I make no guarantees); but don't panic if you mess up, and don't worry if you think you need to break a rule here or there occasionally.

Requirements:

• Somewhere to quarantine things. Ideally, enough space to have several separate groups.
• A sealable pail. This will contain peroxide, and should avoid letting it go bad too quickly.
• Peroxide. Lots of it. Find a bulk source of 7% if possible.
• Plastic gloves. This isn't to protect you from the virus, but from the peroxide.
• Bleach-based dish soap. This is for countertops and any dishes contaminated food touches during preparation.
• Alcohol-based sanitizer. For your hands, possibly doorknobs.
• Cardboard boxes. Best way to isolate contaminated objects for now.
• Full-face P100 class respirator. I recommend the 3M FF-402 with P101 filters, for maximum comfort. (If you must use a half-face respirator, get goggles or at least safety glasses for your eye protection.)

Goals/assumptions:

• Your home and vehicle are clean. Never let them get compromised.

Golden rule above all recommendations: Exercise common sense and critical thinking!

Maintenance:

• Make an event log. When you put a new batch into quarantine, record the date, and calculate the date it should exit the quarantine (maybe add it to a calendar).
• Test your pail of peroxide regularly. Even 0.5% should be enough concentration, but I suggest making sure it visibly reacts to a cut (if you have an open cut, be sure not to get infected through it!) or other biological matter. For convenience and longevity, maintaining at most 3.5% (ie, dilute your 7% with an equal amount of water) seems reasonable. You can top off the pail if it might be too low concentration, but if it's visibly dirty, consider dumping it and starting over.

Groceries or other objects from outside your possession:

• Ideally, have everything delivered.
• If you must do pickup, get a huge cardboard box and put everything in it to avoid contaminating your vehicle. Load it yourself - do not allow the store employee to exhale into your vehicle!
• When possible, quarantine object for 4 weeks.
• If you need it sooner, consider the shipping date rather than delivery date, and logically think about when it was last exposed to another human. Often, products sit in fulfilment centres for months before shipping: if you're careful, you may be able to remove it from its packaging without contaminating the contents (I recommend 2 people).
• Milk and cheese are usually pasturised and sealed well. Just soak them in peroxide and bring inside to a fridge.
• Most fruits and some vegetables can survive peroxide soaking. Wash them with water immediately afterward for best shelf life.
• Frozen cannot reasonably be sanitized. Freezing preserves the virus indefinitely. I recommend designating at least one freezer as contaminated, and just using extra care when handling anything from it.
• Potatoes make too much of a mess in peroxide (you'd have to re-make your pail soon). Instead, I recommend leaving them contaminated in a smaller cardboard box in your fridge. Handle with care, like frozen.
• Breads are best made from yeast in your safe environment, but if you need to buy them, keep them in a cardboard box and be sure to toast or otherwise cook them before consuming.

Outdoors:

• If anyone else has been in your yard for the past 3 hours, stay inside. (Consider exceptions if windy or raining.)
• Maintain a 15 foot (5 metre) perimeter from any border where people may have been.
• Consider posting a sign on your front door that there will be no admittance for any reason due to COVID-19, along with your phone number if they want to talk to you.

• Keep your pail of peroxide, respirator, gloves, and a sanitizer bottle in your vehicle with you, ideally out of sunlight. I keep my pail where the front passenger's legs/feet would go, and cover it with a smaller cardboard box I can put contaminated items into. Note that some sanitizer may be flammable if left in the sun!
• Establish a group of people in your "circle". Everyone must be following the same precautions, or it wastes everyone else's effort. Don't fret about their exceptions to the precautions unless too logically egregious or regular.
• Outside this group, consider everyone else a danger. Avoid interaction, and maintain 15 feet whenever possible.
• When entering the 15-foot airspace of any foreign person for 3 hours prior, wear your P100 respirator.
• Especially avoid any area others have been for 30 minutes prior.
• If you have been anywhere with possible air contamination, as soon as you return home, throw your clothes in the dryer, and take a shower.
• Keep a separate pair of shoes for such scenarios. Rubber boots can be soaked in peroxide for additional safety.