That's scale. Scale only needs to be dislodged. The very best tool to use is a soft or medium bristle tooth brush. You can use soap and water or alcohol or insecticide soap. I use insecticide soap which is not a poison. Wet the area and remove the scale with the brush. Take the opportunity to scrub off all the dried pseudobulb coverings also. Scale can hide under those. Once the scale is dislodged, it will die so don't worry about any that might drop in the media. Just keep your eye out, over the next few weeks, to see if there's any new scale. Scale is an ongoing problem with orchids but if you check the plants regularly it won't become a big problem.
Thank you Tucker85. The whitish fuzz made me doubt it is just a scale.
I have used a toothbrush with 70% rubbing alcohol. Plant is small, only three pseudobulbs, so it didn't take much effort.
I have repotted it too, just in case, and isolated for the time being.
Hope they are all gone.