<Everyone runs off to check on their 1/60 Hikaru>
Yeah I put some UV film on all of my windows at home, plus I have my display case away from direct sunlight. And even then, the blinds are closed over in that area.
There are quite a few things you can do to be cautious, but eventually you reach the line that divides paranoia and acceptance. At this point, you can either continue to protect your item (which will take away from your enjoyment), accept the fact that it is going to yellow over time, OR decide to get out of collecting anything with white plastic, period.
(That's not directed at anyone here - it's just a general p.o.v.)