I installed a nice set of Lloyd mats in my Bahia red 73 2.0 car a several years ago (OK decades) upon removing the mats for cleaning, I noticed the original floor carpet had faded. Bummer! I found a nice used pair of original mats and installed them under the Lloyd mats. Now, they are faded!
I read Lloyd mat instructions and they said not to use on top the original carpet.
Fair warning. Brad

So I guess they want you to remove the original carpet and use their mats in it's place?

Not sure what the mats are made from. But if they are dyed materials some pretty harsh chemicals are used and can remain in the material. Depending on the country of origin the QC can be non existent. My dad always washed the floor mats in any new car. I guess this could be a reason why.

Wow, this is good to know...