Is an agreement valid when one party offers to buy/sell the excess or deficient part of a measure contract for an agreed-upon price?
Chapter on Selling Assets and Fruits
Al-Mughni
Book of Sales
Primary text
If the seller offers the excess portion to the buyer for a price, or the buyer requests it for a price, the other party is not obligated to accept. This is because such a transaction is an exchange requiring mutual consent, and neither party can be compelled into it. If they both consent to the transaction, it is permissible.