Animal products

peace,
 
I asked about animal products and the moral and halakhic implications of this, as is known whether leather and wool are by-products of various industries or not.
There are a variety of solutions to this, for example, with regard to tefillin, it is permissible to use the skin of an animal that died a natural death, without slaughter, and the poskim wrote that this is also preferable and more elegant. The same applies to wool, or theoretically, even home use without pain and in various situations is possible and there is no problem with that.
 
I wanted to know what about the light blue color? Which is produced from blunt-ended thorned scarlet, is there such a way?
 
 
thanks.