Those sights have had a rough time of it. They are ground down and rounded over, as well as rusted. If replacement sights are available that would be option #1. If replacements are not available, or if you don't want to spend the money, then cleaning up and squaring off the rear of the sights with a file is option #2. Repaint with flat black enamel modeling paint. Bright orange on the front sight works well for me.
Thanks. I cleaned dots with tooth brush and alcohol twice. Rear dots are almost 100% clean, front dot started to show paint.
There are glowing paints, orange, yellow and green. Did you use glowing paint? AFAIK green is brightest.
Never had any luck with the glow in the dark paint, just doesn't last very long. I use a 3 coat process for painting front sights: base coat white nail polish, then when dry I put a bright orange acrylic paint then a coat of top coat clear nail polish. Gives a bright sight with a lasting finish.