In Békésszentandrás, the weft threads and weft yarns, which form the base and the frame of the carpet, were always made of cotton fibres. The cotton weft yarn of plant origin was almost always woven or knotted with yarns of animal origin, mostly wool, and less frequently with caterpillar silk. Wool carpets with silk were made in Békésszentandrás only between 1920 and 1935, and even then rarely during this short period.

In the 1920s, it is likely that much of the work was done with home-made yarns from the wool of the local Racka sheep grazing on the outskirts of the settlement, but this changed by the 1930s. In 1936, a licence was applied for the establishment of a wool spinning mill, which suggests that yarn was still produced in Békésszentandrás, although not always from wool from nearby sources. There is conflicting information about how much of the material was collected locally and how much had to be purchased.

It is important to note that to ensure the high quality of the carpets, only live wool was used, instead of so-called dead wool. The distinction between the two types is appropriate to the name: the wool removed during the processing of animal flesh is known as "dead wool". According to experts, the difference is striking, so the wool used for the yarns in Békésszentandrás could only come from live animals. During the shortage of raw material during the war years, the high quality was changed by mixing sheep's wool with a certain amount of goats' hair.

In 1967, a large-scale yarn rescue programme was launched in Békésszentandrás, during which huge quantities of yarn waste from Western carpet factories, pressed into bales, were purchased. By developing a recycling process, the carpet weaving mill created a new product type, which was named “merinó”. The raw material for the merinó carpets made here was wool waste that had been previously burned by the processing industry, but which was used to produce high-quality yarn in Békésszentandrás. This extraordinary initiative is a contemporary example of recycling and sustainability.