When shipping baseball cards, proper packaging is essential to ensure the cards arrive safely at their destination. As baseball cards can be valuable assets, taking the time to package them correctly will help prevent damage during transit.

The first step is to select a shipping box or envelope sized appropriately for the number of cards being shipped. For 50 standard size baseball cards, a box measuring approximately 12x9x2 inches would provide enough interior space. Ensure the box is in good condition with no rips, tears or loose flaps. New boxes are preferable to reused boxes to avoid potential damage.

Inside the box, use bubble wrap, air pillows or packing peanuts to cushion the layers of cards during transport. Lay down an initial cushioning layer that takes up around 1/3 of the box’s interior space. This will absorb impacts from any side of the box that may get bumped. Peanuts or air pillows work well as they fully fill any voids.

Next, slip each individual baseball card into a penny sleeve protector. These thin plastic sleeves help prevent scratches and fingerprint smudges. Lay the sleeved cards out in rows on the initial cushioning layer, overlapping edges slightly to reduce movements. After 5-10 cards, add another layer of cushioning material over the laid out cards.

Continue alternating layers of cards and cushioning until all 50 cards are placed in the box, ending with a thicker cushioning layer on top. This sandwiches the cards securely between padding. Make sure cards are not able to slide around freely inside by taping partial sheets of bubble wrap or air pillows over any open spaces.

Once filled, seal the shipping box tightly with clear packing tape in both directions along all seams and flaps. Applying tape around the entire perimeter reinforcement helps withstand impacts. Weigh the sealed box and note the weight on the outside for shipping label accuracy. Proper labeling also assists safe deliver.

For lower value cards, a bubble mailer affixed with tape all around can work as well. Place the penny sleeved cards into pliable sheet protectors that are then inserted into the mailer pouch. Seal the mailer by firmly taping down all open edges and surfaces.

Whichever shipping container used, be sure to purchase adequate insurance for the cards’ worth and clearly write “FRAGILE” on the box in large letters. This alerts handlers to exercise extra care. Optionally noting “BASEBALL CARDS” provides context of the contents.

Select a reliable carrier like USPS, UPS or FedEx that tracks shipments. Ask for delivery confirmation requiring a signature for proof of delivery and recourse if issues arise. Careful preparation and choice of shipper helps get valuable baseball card collections safely into collectors’ hands. Proper packaging as outlined guards against damage or loss, keeping cherished cards in mint condition.