I just got an old set of kalimar Model K70...

The water drop marks you are seeing may be seperation of the lens coating. Most binoculars after WW2 have some form of anti-relective coating on the lens. This is applied to the glass surfaces in varying degress by various manufacturers. Its intended purpose is to reduce the amount of light that is reflected off the glass so that the image you see is brighter. Your windows at home that aren't covered actually don;t allow all of the light to come through!
What they all have in common is that the coating is applied onto the glass. Over time like anything that is stuck on or painted it can begin to peel off.
You could try asking a repair place if they caqn replace the lens but most likely they would need to change both so that they have the same coating. The binoculars are worth more for sentimental value than the cost of repair as a similar replacement set would cost as much. Zoom binoculars are not known for their optical quality. Often this 'watermark' effect doesn not interfere with the view. If your sentiments say fix them regardless do so. If not hold onto them as a keep sake.