best way to clean radiator

I went for a 8 hour ride last weekend and got really muddy. I cleaned it well but today when I went it started to over heat after 20 minutes or so. I diagnosed it to the rad being blocked by mud. I after letting it cool down I got it home and cleaned the atv with the pressure washer. I then went with just the hose and washed the rad our and used a brush you use to wash dishes. Just wondering if there is any better way to clean the rad as I don’t want this to happen again. This is the first time this has happened but also the first time I have gone for such a big ride with this machine