When in doubt, do the easy thing first.
Try spraying them off with a hard, fine mist of water.
If that doesn't work, wipe gently with rubbing alcohol on a swab or bit of tissue.
Still there? Consider spraying with insecticidal soap, if you still can't get a pest ID. To me, that looks like an advanced infestation of SOMETHING. I just hope those bumps are not egg masses.
Do you have enough room that you can quarantine them to protect other houseplants?
