We all have favorite quilting tools, some of them are “found” in the real world!
Have you tried these yet? I’ve been using them for a couple of years now.
I find these work at LEAST as well as the ones I have purchased at the quilt shops and the benefit is, they are sooo much cheaper that I actually change my blades in my rotary cutter more frequently. You DO have to separate the blades VERY carefully as there is a layer of oil on the blades. I simply slide the blades apart, take one and then re-tape the package closed with whatever tape you have in your sewing area.
These little gems are from Harbor Freight are in with the carpet laying supplies. They run $1.49 for the two blades. You can use the 20% coupon that comes in your newspaper, too! I usually stock up on them when they are go on sale for .99/pkg. Can’t beat the price and I am certain they are as sharp, if not sharper, than official rotary blades.
You can buy them online, too, of course. They are called “Replacement Carpet Cutter Blades” and are item 97642. Here is a link: Replacement Carpet Cutter Blades.