I starch a lot . Yes I have seen the solution start to change color.. it goes from a milky white to getting a tinge of yellow to it and if I spray it on pure white fabric .. the spray pattern will show up as a faint stain. This "stain/discoloration" does wash out with the starch. This happens when the weather gets warmer... so I mix smaller batches. As far as the fabric I have some starched fabrics for years... but I de-humidify.... and no bug issues. So the questions is how humid is your storage area? If its has a high humidity starch as you need for each project.