You probably nailed it right on the head in your description of one of the pictures. It’s probably grease build up. It is imposible to say for sure without actually being there though. Get a good degreaser product like 409 or Fantastic and have at it! If it is really bad on painted surfaces, you might have to encapsolate it after cleaning as much as possible before repainting. Kilz and Zindzer work wonders, but the surface can’t be slick. The ultimate fix would be to replace any damaged surfaces, but that can become unrealistic in most cases.
Say no to drugs. Like Scott said, poor housekeeping. You have cooking fats all over the place mixed with fly poop.
Poor ventilation in bath and kitchen. Put in a high quality bath fan and a high quality range hood/fan and add in some proper house-keeping habits as well as a diet change and the reduction in mess will be very noticible.
Still see cheaper fans even in higher end houses. Did a first year warranty inspection on a $1.5 million house 2 years ago- none of the 5 bathroom fans met codes and 1 was dead…at 11 months. That was the smallest of the house problems!!!
Less than 1 in 75-100 houses I’ve inspected have good or even code ventilation systems!!
Exactly what I was thinking,… poor housekeeping and heavy smokers. Cigarette smoke tar will leave a yellowish, sticky film on every surface, including ceiling, walls, light fixtures, etc. Last picture is an obvious plumbing leak with mold.