I've discussed this numerous times but i wanted to show an example of what i am talking about. I normally recommend leaving plastic parts that need to be straightened in a car on a hot day or setting it on the defroster in the winter (and in the cases of resin parts- just running them under hot tap water). a lot of people are skeptical and boil the parts or use a heat gun and really risk damaging the parts.
I have started sorting and selling some of my grown son's childhood toys among them his 12" action figures. this motorcycle helmet has been sitting in the bottom of a tote for 15 years and was deformed badly. to fix it i took it to work with me and left the defroster on high heat and just let it warm the plastic for about 45 minutes. the plastic was then very soft and supple and MOSTLY relaxed back into it's natural shape, while it was cooling i tweaked it's shape a bit and it locked these tweaks in when it reached room temperature. you can do this as many times as you like without damaging the parts, and it allows you to bend the plastic without stressing or breaking it.
hope this helps someone.
109A094E-033B-487C-AA26-E5BC8B2ADD00 by hotdog stuff, on Flickr
600C4B14-BE78-4EF9-9454-D7B5717A6012 by hotdog stuff, on Flickr
1CB534F0-148B-4E09-962D-64BC294F8E9D by hotdog stuff, on Flickr