Recently I had to use my DeLorean has my daily driver while my other car was getting some hail damage repaired. Of course it comes at the hottest time of the year so it was sitting outside at my office for 9 hours in the 90 degree sun. Every day I come out, there would be a noticeable haze on the inside of the windshield. Each morning I would clean it with Sprayway and blue window towels, only to have it reappear later in the day. This continued for four days until I got my other car back and haven't driven the D since (just been busy).
Keep in mind I don't drive the car that often but in my 16 years of ownership I've never seen this happen ! I haven't cleaned the interior lately, but when I do it is some typical leather care cleaner for the seats and Meguires Natural Shine Protectant for the dash and other surfaces.
Definitely not heater core, I was running the A/C non-stop and I know what antifreeze smells like.
Ideas? This morning I'm going to clean the interior with some warm soapy water, perhaps there is some oil from other cleaners that has built up over the years that is coming out.
FWIW I replaced the windshield with a new one from DMCMW about 3 years ago.
Andy