Commercially available butter is typically wrapped in wax paper or packed in a tub. Either form must be shipped in low temperatures to prevent the butter from melting or going stale. Here are some tips on how to properly pack and ship butter.
Freeze the stick or tub of butter and place inside a resealable plastic bag. The bag will prevent messy leaks.
Meanwhile, prepare your insulated shipping box. You can line the inside walls and bottom of a cardboard box with sheets of foam insulation board. Then place the frozen and wrapped butter inside. Add a cold pack (amount depends on the number of items and size of the package). Fill any empty space with packing peanuts to prevent movement. Place another sheet of insulation board on top before closing the box. Alternatively, you can use a store-bought cooler and place it inside a shipping box.
Seal the box with packaging tape and address the package. Ship using overnight delivery or any expedited delivery option.