Brown staining on White plastic - What is it?

[Rabbit Leader]

A question I’ve been meaning to ask for ages, however thought I’d post it now just before I start the Airfix Short Skyvan for the up and coming High Wings GB. So this is a photo of my 1974 release Skyvan. You will see some brown (almost nicotine like) straining around the edges of most if not all of the kits parts. I’ve washed all the parts in soapy water but this has had no effect. 

 

 

The plastic still appears quite hard and crisp, however I don’t know what this staining is? I bought this kit a few years ago from a friend who lived in Townsville, Australia - a pretty hot and humid place for most of the year. The original internal bag was still sealed so not sure if this had anything to do with it. My mate was also a non-smoker, so I’ve discounted that theory too.
 

So my question is: Does anyone know what this staining is and is it likely to impede my build in any way? 

Cheers and thanks.. Dave 

[dogsbody]

As someone who grew up on a farm with various animals and who also assisted with the raising of 3 children, I'm a bit wary of " brown " stains on anything. 

 

It's usually something unpleasant and smelly!

 

 

 

 

Chris

[bentwaters81tfw]

Possible releasing fluid from the mould. I tend to wash kits in warm soapy water and leave them to air dry - certainly resin ones.

Tip - use a bowl or put the plug in the sink. You don't want to lose any parts.

[pigsty]

As bentwaters81tfw says, that sort of stain is usually mould release agent.  If your kit's fairly new you can still feel it - slightly greasy.  If that thing's been in its bags for nearly forty years, in the heat, and if you've already washed it, my guess is the agent has all evaporated but has left a discolouration in the plastic.  It should be nothing more than colour - harmless enough.  But as you have some on the runners as well as the parts, for added reassurance you could test paint and glue on that before committing to the actual model.

[Black Knight]

I've come across this afore and a darker brown version which resembles spilt coffee

Both come off, in my experience anyways, easily with MrMuscle oven cleaner

[Rabbit Leader]

1 hour ago, Black Knight said:

I've come across this afore and a darker brown version which resembles spilt coffee

Both come off, in my experience anyways, easily with MrMuscle oven cleaner

 

Thanks BK. I might give the Mr. Muscle treatment a go, although have never tried this before. I take it it's just a spray and leave for a few hours and inspect the results later? 

Cheers.. Dave 

[Black Knight]

Spray on, enclose in a plastic bag or box overnight, then wash off with water with vinegar in it