Is it possible without the heater core being damaged? I checked the prices at the usps international calculator.
Global Priority Mail - Flat-rate Envelope (large) 3 - 5 Days $9.00 9-1/2" x 12-1/2"
Global Priority Mail - Flat-rate Envelope (small) 3 - 5 Days $5.00 6" x 10"
Global Priority Mail - Flat-rate Envelope (large) 3 - 5 Days $9.00 9-1/2" x 12-1/2"
Global Priority Mail - Flat-rate Envelope (small) 3 - 5 Days $5.00 6" x 10"