In the rule “Buildings” add a subrule titled “Recycling” and give it the following text:

As a Seasonal action, a Settler may remove one Building that is in their Settlement and add half of the Cost of that Building to their Stockpile, rounded down to the nearest integer for each item type that was part of the original Cost. During this action, for each item type in the original Cost that was 1 and would be rounded down to 0 after halving it, that Settler should use the public Dice Roller to roll DICE2, and on a result of 2, they add 1 of that item type to their Stockpile instead of 0.