I've been storing my Berghammer Lite for a long time and I've noticed blue-black sediment at the bottom of the container, should I not use it?

The blue-black precipitate is an important chemical agent that has settled out due to specific gravity decomposition after long-term storage. There is no problem as a product, so please shake it well before pouring it into the engine. When the oil is circulated in the engine, the heat of the engine will agitate the oil and lead to better performance.