Q: Am I obligated to pay for destroying a check that was made out to someone else?

A: The Gemara (Bava Metzia 98a-b) teaches that one who burns a loan document is liable for the value of the loan as garmi, even though the document itself is not of inherent value (C.M. 386:2). The Rosh explains that this is because he actively damaged his friend’s property and the loss is definite; additionally, the damage is done immediately. The same would seem to be true if you destroyed a check (Pischei Choshen, Nezikin 3:[50]).

You can only be made to pay, though, if you admit (or there is evidence) to the amount of the check or loan document; the owner is not believed as to its amount (see Shach 386:13). If witnesses can testify about the loan document and the lender can collect on the basis of their testimony, you would only be liable for the value of the paper itself.

If you destroyed other legal documents — e.g. a title to a car or house, or legal evidence that caused one to lose a court case — this is usually not considered garmi, but rather grama, for which there is only a moral obligation (P.C., Nezikin 3:[51]).