I have several vintage Corgi and Dinky cars in their original boxes where the boxes have various tears and delaminations.

What is the best way to preserve/repair these boxes?

I would like to place some kind of tape on the inside of these areas to stabilize, strengthen, and prevent further tearing. Is this the best solution? What type of tape? I don't want to use something that will yellow and dry out. Is there some type of archival tape that will remain clear and flexible?

I want to be able to open the boxes and take the cars out sometimes and the boxes need to be strong enough to withstand this handling. Thanks.

Good question.
I think you may have hit on something when you said "archival".
Maybe you could go to your local historical society and ask how they handle similar problems.
Also if you happen to have a really good artist supply store in your area, someone there might know.
I'm tempted to say white glue might work, but that's just a guess.
Possibly a glue with more flexibility would be needed.
Good luck!
LMX

I agree, good question. I also agree that with the delamination or small tears that white glue would be the way to go. I recall seeing a tutorial on restoring boxes. That guy used an iron on low to smooth out the boxes and reseal the laminations. It will also help to cure the glue but you will have to use something like wax paper between the boxes walls so they don't inadvertantly get stuck together. Obviously you need to practice on boxes that don't matter first before moving on to the more historical pieces.

You might use clear packing tape to reinforce the inside of flaps. It is generally a bit thinker than regular cellophane tape and hopefully less likely to yellow over time. Good luck!

Thanks for the suggestions guys. I did some looking around and ordered these two things:

Lineco Transparent Mending Tissue 1/2" x 600" roll
Linco's Transparent Mending Tissue is a unique combination of a strong, very thin, acid-free tissue, coated with an acid-free adhesive. It is easy to use, non-yellowing, and widely accepted as a truly archival repair tissue. While repairs with the tape are permanent, it may be removed with common mineral spirits.

Lineco White Neutral pH Adhesive 4oz squeeze bottle
Lineco's White Neutral pH Adhesive's polyvinyl acetate (PVA) formula was specifically designed for preservation materials. It has excellent lay-flat properties, is fast setting, clear when dry, re-moistenable with water, and will not become brittle with age.

The first will be for mending tears and the second for sealing delaminations.