“That which he stole” — as he stole it; if he stole a coin and it was invalidated… he says to him “here is yours before you.”
In the sugya: Where the change is not legally recognized as a “change” that acquires title, the thief may return the object as is. Invalidated coins, spoiled fruit, and similar cases remain “as stolen.”
Type of Learning
Diyuk of unchanged form — non-legal changes leave the object returnable as is.
What Is Learned
Invalidated coins, spoiled fruit, soured wine, and similar cases remain “as stolen.” The thief may say “here is yours before you” and discharge the obligation by returning the object in its present state.