Any techniques for cleaning an HDRI sky properly? Also HDRI Sky discussion

[burnin]

Tools for manipulation of HDRIs:

• https://www.lightmap.co.uk/
• HDR_ProStudio for Blender 2.8 - FREE plugin + source code
  … or whatever Image Editor supporting 32bpc

Sky HDRIs (w/o the ground): https://www.cgskies.com/skies.php