I need to send in my receipt, but what if my receipt is also my warranty? /

Many shops will print a different warranty receipt that it is not part of the purchase receipt. If this is not the case, be sure to make a copy/photo of your purchase receipt for warranty matters, or have a copy of the receipt stamped at EU-Customs so you can keep the original (customs will only stamp a copy if you can show them the original at the same time).