Just for those 'thinking' about the offer. Carpets are essentially made by adding 'Pile' to a backing material and so can be looked at as having two layers plus, in the case of foam backed carpets, a cushion layer.
The Pile can comprise mixtures of Wool, Nylon, Polyester and Acryrilic, and tuft height will usually vary in depth from about 4mm to 24mm. The backing can be mainly a mixture of Jute, Sizal and Polypropylene. The substrate foam will typically be between 40 - 90% chalk. An old carpet is unlikely to have any residual chemical fibre coatings from the manufacturing processes, and any chemical dyestuffs will be inert.
As to the use of old carpet. It will have a covering value for a time until the fibres comprising it decay.
I do like the idea of re-cycling but wonder whether, in addition to being used as a covering, they could also used as a lining for some sub earth activities where manure needs to be buried at a depth.