The Mailroom shift rules and puzzles: what each day adds

The rule that changes on every shift is written down rather than implied: read the notes in the directory before you sort, and burn any letter whose street address is wrong. Each day also adds one mechanic of its own. Here is what day 1 to day 5 actually ask for, and what to do when the assistant stops bringing mail.

The Rule That Changes Every Shift

Read the day's notes in the directory book first. New rules for handling mail are introduced each day, and the notes are where they are written down.
Check the street address too, not just the name and the department. Rarely, the street address on a letter is also wrong, and those letters must be burned even when the name checks out.
Do not carry day 1's routine forward. The three desk checks in mail sorting rules are the standing policy; the day's notes add to them.

Day 1: The Punch Card and the Whole Frog

Punch the time clock. The punch card is the first task of the shift and the day does not start without it.
Send the frog whole, through tube 2. The instructions for the day say to put the frog in tube 2, and that is what clears it. A ground-up frog, or a frog sent up a different tube, does not.
Read the instructions on the card and on the frog tube itself. They are not the same as the order you were given from the desk.
Ring the bell if the day stalls. The bell summons the assistant and brings more mail, which is enough to keep the shift moving.

Day 2: The Recipe Card and the Bottle in the Canister

Find the order. The recipe rides on one of the pieces of mail itself: the card states the minimum mL the mixture has to reach and lists the ingredients with their percentages at the bottom. The back of the card carries the addressee, exactly like any other mail.
Check which body part the card wants. It asks for frog legs, frog meat or frog eyes, and hovering over a body part tells you what it is. Grabbing frog meat when the card wanted frog legs is the classic day-2 mistake.
Grind to the proportions. You can grind the ingredients one at a time or all of them at once, but the mix has to hit the percentages on the card.
Pour into a bottle, then put the bottle in a canister. The canister is what goes up the tube, to the floor printed on the back of the card. A loose mixture, or a bottle sent without its canister, is not a delivery.

Day 3: The Security Room, the Wall and the Spell Book

Go into the security room and look at the wall. That is where Pepe is, and the wall is the point of the day.
Use the spell book in the security room. The spell is there for a reason, and the book is the only place you get it.
Burn all of Pepe's mail in the security room. On this day that is a task, not junk mail.

Day 4: The Blood-and-Diamond Ritual and the Unused Meat

Cut the meat with the knife. Day 4 is the cutting day, and the meat is the first ingredient of the ritual.
Burn the unused meat. The Flesh and Blood note tells you to burn all the meat you did not use.
Watch that instruction. Burning it counts as a mistake on a Perfect day even though the note says to burn it, and the developer has said the two do not agree and that it will be fixed in a future update. Feeding the extra meat to the crow is what the achievement list says to do instead.
Feed the extra meat to the crow. A bird has to eat, and this is what keeps the crow from becoming a problem later in the week.

Day 5: The Frog's Heart and the Elevator Drop

Talk to the frog. In his dialogue he asks for your help to cut his heart out, and the heart is the final ingredient of the ritual.
Wait for the frog to return. He comes back on day 5 with the other ingredients, and the diamond cannot be used until he does.
Check the spell book first. On day 5 everything floats away from you, and the spell is what holds the room down. If you did not know there was a spell, you will be trying to cut meat while the room drifts apart.
Take the elevator down. Day 5 ends with the drop, and the spell that unlocks the elevator is the last errand on the list — hell's exit and the locked door has that errand list.

When the Assistant Stops Bringing Mail

Push the chandelier. It looks like set dressing, but pushing the swinging chandelier of skulls drops a few pieces of mail onto the desk, and that is enough to finish the day. Players who thought they had hit a bug used this and carried on.
Use the red option in the pause menu. It returns everything important back to the table, which is what you want when something has gone missing in the dark.
Restart the day. If the mail does not come back after the day 4 cutscene, restarting the day is the fix — the assistant brings more and the shift continues.

Finding a Specimen That Wandered Off

The special ability highlights everything in the mailroom that will help you find the frog if he wandered away from the desk or jumped out of the toilet. On keyboard it is F, and on an Xbox controller it is the Right Button. It is the fastest way back to a missing specimen, because a frog that has left the bench is also not where the delivery routine expects it.

Where Each Shift's Work Is Covered

The frog that goes up the tube and the frog that goes on the bench are two different jobs — frogs.
The grind, pour, weigh and chop stations on the processing bench — potion crafting.
The three desk checks and the junk mail policy that stay the same every shift — mail sorting rules.
The full shift from clocking in to clocking out — the walkthrough.