So I think it should be a commercial choice to fly or not to fly as engines will last maybe only 3000 hours on wing rather then 5000 hours but there is no immidiate danger!!!
I hope they last a darn site longer than 5000hrs!
The build up that welds itself onto the turbine blade surface is not such a problem except for the reduction in efficiency and an increased fuel burn. The major problem lies in the build up inside the blades that blocks the cooling holes and leads eventually to a burn through.
The effects on the rest of the airframe: Pitot static port contamination and the effects of erosion (sandblasting!). Plus of course, if it should rain it turns nicely acidic!