Problem with fireflies and denoise on surfaces Lately I have this problem with my renders when after rendering I get weird light effects (fiereflies) especially on walls that are just plain coloured. Like in this render 



( It's closed room with 5 area lights from ceiling and one from lamp) I get this effect, especially around and at objects that are "ceramic".
I tried different things that have worked in different projects, but with this one seems like nothing works (render was made and denoised with 2000 samples).

Here is 2000 samples without denoising 



Thank you for any advice!
These "splotches" are because of Blender's default denoiser. They can be removed by increasing the denoising radius (something like 14 px or so). However, it has other serious side effects (eg, incorrectly blurring the sharp shadows of things like individual leaves of a plant). Try using Intel's Open Image Denoiser in compositor, or Nvidia Optix denoiser (https://www.youtube.com/watch?v=eGAjsSNtX6E) instead. They're relatively better denoisers.