Translation:Shulchan Aruch/Choshen Mishpat/52
Paragraph 1- A document that contains explicit interest cannot be used to collect the interest but may be used to collect the principal, even from encumbered properties. If, however, the lender included the principal with the interest, the document is invalid because the lender will come to also collect the interest. If the defendant confesses, however, he must pay back the principal. There are those that say that he is exempt because we fine the lender and therefore the borrower does not have to pay. If, however, the lender lent the money via a messenger and the messenger made the document and included the principal with the interest, the lender may collect the principal because he can say to the messenger, “I sent you to benefit me and not to harm me by including the principal with the interest.” See Yoreh Deah Siman 161 for more on these laws. If a document is brought in front of us with a tear made by a court, which is a tear in the place of the witnesses, date and the substantive parts of the document or if it was torn vertically and horizontally, the document is invalid. If it is evident that the tear was done with a knife, the document is invalid even if it was not done vertically and horizontally. If the document was torn into two, it is worse than a court-made tear and would be invalid. If there are witnesses that the document was torn accidentally, the document has the same rules as a case where the document was erased, as was explained above in Siman 41. If the tear was not court-made but [version of the Sma] it appears to the judge that the court tore it and a party added to the tear in order to hide the court-made tear, one could not collect with it. Otherwise, we would not be concerned.
Paragraph 2- If a document was erased or blurred out and the form was still recognizable, the document is valid. Otherwise, it would be invalid. If the document rotted or was made like a sieve, it is valid. If a moth or mice ate the document at the top, so long as the names of the lender and borrower and the primary part of the context is at the end, the document is valid.