Buy the envelope, stamp, and any mailed material (eg paper) far from your home.
Exclusively handle all the materials to be sent in a clean environment far from your normal haunts. You may want to wear a hair net, breathing mask, and gloves. Do not lick the stamp or envelope.
Be careful about handwriting anything, if authorities may have any samples of your handwriting — as for example on prior letters addressed, or archived forms filed. Also, do not use a computer laser/inkjet printer, which may add unique invisible tracking codes.
After leaving behind your own phone, be sure not to use a vehicle with its own phone (OnStar etc) or any RFID transponders (eg tolltags, which can be read for traffic jam analysis even on non-toll motorways). Similarly, put aside any personal ID or payment cards (passports, some driver's licenses, mass-transit stored-value cards, etc) which may have remotely-readable RFID transponders.
Try to arrange for your phone, computer, or residence to continue giving off its usual signals of your presence – so that the period of the letter mailing doesn't show up as a suspiciously idle time for you.
Avoid all private and public surveillance cameras, or disguise yourself (and your car's license plate from automated readers).
Still:
Even with all these steps, it's likely the individual's capability to opt out, with effort, from being tracked will soon be obsolete. It will be too cheap and appealing to video-record all public spaces, or even regularly dust all public spaces with unique molecular tags so that when examining an artifact later (a letter, vehicle, article of clothing, etc), all other places it has recently been are evident to careful analysis.
Buy the envelope, stamp, and any mailed material (eg paper) far from your home.
Exclusively handle all the materials to be sent in a clean environment far from your normal haunts. You may want to wear a hair net, breathing mask, and gloves. Do not lick the stamp or envelope.
Be careful about handwriting anything, if authorities may have any samples of your handwriting — as for example on prior letters addressed, or archived forms filed. Also, do not use a computer laser/inkjet printer, which may add unique invisible tracking codes.
After leaving behind your own phone, be sure not to use a vehicle with its own phone (OnStar etc) or any RFID transponders (eg tolltags, which can be read for traffic jam analysis even on non-toll motorways). Similarly, put aside any personal ID or payment cards (passports, some driver's licenses, mass-transit stored-value cards, etc) which may have remotely-readable RFID transponders.
Try to arrange for your phone, computer, or residence to continue giving off its usual signals of your presence – so that the period of the letter mailing doesn't show up as a suspiciously idle time for you.
Avoid all private and public surveillance cameras, or disguise yourself (and your car's license plate from automated readers).
Still:
Even with all these steps, it's likely the individual's capability to opt out, with effort, from being tracked will soon be obsolete. It will be too cheap and appealing to video-record all public spaces, or even regularly dust all public spaces with unique molecular tags so that when examining an artifact later (a letter, vehicle, article of clothing, etc), all other places it has recently been are evident to careful analysis.