Don't Try This At Home With Your Kellogg's Baseball Cards

I've opened ten packs of 1970 Kellogg's baseball cards in the last few years.  They still have great color and look as new as they did in 1970.  Unfortunately some of the packs were a bit curled when I purchased them.

This doesn't look too curved.

So what mistake did I make?  I put the cards in top loaders.  Of the seven packs that I opened I now have a few cards that have cracked.

 Lots of questions come to mind.  To describe the level of curvature I still need to come up with a scale.  More on that later.  These weren't curved much but it was noticeable.   Now I feel the need to check all of my cards in top loaders to take cards out that are not flat.  I did buy lots with some curvature so this could take a while.

Were these cards going to crack anyway or did I cause this?

Should I put them in nine-pocket pages and store them standing up like I do lots of my Kellogg's cards?

Should I stop collecting Kellogg's cards?   Nah.

 Like the Harrelson, this Laboy was the first card in the pack.  The top left corner was damaged before I opened this pack.  Are top cards more susceptible to crack after opening?

The big questions relate to the PSA numbers that I've been discussing this week.  I've seen many comments online and ebay sales with Kellogg's cards that have been graded but are now cracked.  How does that impact the numbers that PSA releases?  No one is going back to them to get those cards regraded (down-graded I'm sure).

I've also been told that PSA will grade cards that are curved.  Well, that make me fearful of buying any graded Kellogg's card except 1973s since I wouldn't know if the card had a curl to it when it was slabbed by PSA.  If the cards that I place in a top loader, which still allows the card to curl a bit, can crack then a slabbed card would seem to be more likely to crack.