PSA asks that use send them in Card Saver I's. With Covid, the manufacturing of card savers started drying up and with higher demand due to the explosion of interest during the pandemic, people started reselling the plastic card saver's for 3x or 4x on ebay. It's started to normalize a bit now as Cardboard Gold, the original manufacturer, begins to catch up. I sent one order recently in top loaders even though PSA advises not to. However, PSA agreed to accept toploaders for awhile during the shortage. I put them in penny sleeves then into top loaders. They were much harder to secure than the old card savers. Generally you want to put them in a stack of 15-20, but cardboard out and put at each end and secure them with a rubber band. That way there's no movement and they are secure.
That last order was just for 86 Fleer commons which at one point I'd passed on grading. It used to be if you didn't get a grade of 9 or 10 you didn't want to send those in. Today if you can get 8's, even some 7's they are worth it even on the commons. They have increased their economy grading fee though from $10 to $12. Like a true expert I sent my last order in less than a week after the price increase so I could pay an extra $160 or so.