I replaced a brake caliper today and used up my entire brake fluid in the car.

Is there a way to plug or crimp the brake fluid lines to stop this waste?

Also, I have two bricks; after I replaced the caliper, I noted that the fluid was yellow/clear through the brake fluid reservoir. However, in my other brick, whose fluid I changed just one year ago, the fluid was black/Coca Cola colored (that is, looking at the inside and outside of the reservoir. When I drew up the fluid through a clean tube to examine it, it was amber/yellow.