My scoop has 12mm holes, (about half an inch) and our smallest coins are 16mm, so Im good for the coins. Of course smaller things will go through, but as Tom said, you will know when something goes through, so you can still find it, its not lost. I dont use my scoop for sifting, except in the water, our wet sand is almost like mud, so you can sift all day, and it wont leave the scoop, a screen would never work. In the dry or wet sand, I just dump the contents of the scoop next to the hole and check if there is anything there. In the water, its easy to sift out. I tried pulling a float, but it didnt work any better, and in the surf,
always afraid that it would turn over, and dump out something good.
Sometimes I see people looking for the perfect scoop and one that will last forever, but there is no such thing. Just like all tools, some work good in some places, and others work better in other. You just need to start somewhere, and go from there, its good to ask questions and get opinions, but through your own experience, will learn what is best. My scoop works good, but it sure is heavy!! On my next one, I will keep that in mind. Just like detectors, the best today, will be nothing in 20 years.