The color you chose to dye your carpet is dependent on the previous color of your carpet.
Can you re dye a dark blue carpet to gray.
When carpet dying you can only go darker and never lighter so chose your color well.
But keep in mind it will be permanent so be sure you can commit before you proceed.
Read the dye packaging carefully to make sure it is safe for use on these materials.
Some local fabric carpet and home supply stores as well as a variety of online retailers sell carpet dye in an assortment of standard colors.
Only dye your carpet if you are sure it is wool or nylon.
Dye carpet give your plush a fresh clean stain free reboot with the guidance here.