I always hated fooling with those factory bino lense covers....and I picked this up from Jeff 'tippit' Springer, and I thought I'd share this in hopes of saving people some grief fighting lense covers.
1st.....take you a piece of fabric, I've used polar fleece, and eye ball the size you will need depending on the size of your binos. Feel free to cut over sized as you can trim to a better fit after your done if need be.
2nd....cut a slit where the red Xs are, again check the size of your binos. You want to come down far enough from the top edge to allow enough fabric to cover the lenses, and don't cut too close to the side edges.
3rd...Connect the fabric to the binos through the slits as shown
Here's the way the cover should look when in use..
When you wan to view, simply raise up the 'flap' and let it fall back out of the way, and flap it back over when you are done.
When storing, a simple rubber band will keep the flap down and your lenses clean.