One cannot be too careful. Incidentally, I bought several packages of the Lighthouse capsules sized for the Presidential Dollars. I pass them out to friends as mementos/gifts.
I love air tites. I use Caps Albums and think they look and work wonderful. They are a pain to open though.
I know that the 1986 Mexico Libertad 1 oz coins will not fit in the Lighthouse capsules. They are smaller in diameter but are much thicker than the subsequent years' Libertads. So, if Piedforts are just as thick or thicker, then it won't fit. If Air-Tites offer a "10" in seal-ability, and Mylar flips offer a "1" in seal-ability, then IMO Quadrums (Lighthouse) offer a "5-6". Given the two extremes at the ends, it's a decent seal. If you put the Quadrums in 12-pocket flips, then a little more protection is given along with a nice presentation. Here's an old photo of a setup I had before. It's similar to what I have now. It's not the best photo to show how Lighthouse Quadrum capsules look inside of 12-pocket pages, but I think the idea gets across.
That's where my little Swiss Army knife comes in handy. Not quite as sharp and pointy as an X-acto, so it doesn't damage the capsule if I get excited.
Yeah, you need a finer edge than a typical pocket knife offers. If you don't have an X-acto, a box knife blade might work too. It's really not too involved. Once you find a spot where the X-acto blade can slip in a little, you just wiggle it left and right a few times and it'll create enough space to let your thumbnail do the rest.
Bellman has been off the forum for a while, but you can not solicit buying/Sell/Trade except in the classified section. Also do not give your phone or address, or the bots reading us will sell them. Jim