Do Methylated Spirits Damage Plastic?
If you are wanting to clean some plastic with Methylated spirits then you may well be wondering if they will do any damage to the plastic. I happen to have a bottle of methylated spirits on hand so let’s find out.
First things first, the spirits come in a plastic bottle. So that’s a good sign that we shouldn’t see much damage I would say. Otherwise, I think they would have chosen a better storage option.

This is not a direct indication that Methylated spirit will not damage plastic though. There are lots of different plastics that can react differently with different chemicals. Because of this, I won’t truly be able to say they work with all plastics but all I can do is test a few plastics and situations.
Plastic Pen
So this is hard plastic, part clear, part coloured. I have disassembled a pen and left it in Methylated spirits for 48 hours. Let’s see if anything happened.

Above you can see the pen soaking away in the spirit. Time to pull it out and see if anything has happened.

Absolutely nothing has happened to any part of the pen. Even after being fully submerged in the Methylated Spirit for 48 hours. Every part is good as new, including the smaller parts.

Here you can see that the pen is still good as new. I held it in my hand just to show that it hasn’t gone soft or bent or anything like that.
So, what to test next? Well, I decided to see if rubbing the spirit would do anything. This sometimes happens when you are scrubbing away and working the cleaning product into the plastic surface.
Scrubbing Clear Plastic
I just grabbed some clear plastic from an old Pepsi bottle and cut a little square out, this is what I will be testing.

Let’s get some Methylated Spirit scrubbing done and see if anything happens to this plastic.

Here I am scrubbing away using plenty of Methylated spirit and force, lets see if anything happens to the plastic.
And below you can see the plastic after cleaning.

Nothing has happened to the plastic, it is still crystal clear.
Conclusion
So far so good for plastic, nothing I have tested so far has been even the tiniest bit damaged. So I am pretty confident in saying Methylated spirit doesn’t damage plastic.
If you have another type of plastic you want to be tested just let me know in the comments.