brakes not working right

First off, thanks for the help. It's great having somewhere to ask these questions. It's been 30 years since I last got serious about working on cars. Second, this gives me a couple of directions to go. All parts and hoses are new, with the exception of the hard lines going to the back brakes. They seem good, at least on the outside, but could easily have crud inside. I will change those too soon. I cleaned out the reservoir, which somehow did have some grit in there, and refilled the thing, and so far, the brakes are no longer sticking. They seem to work better. so I suspect at this time, there was some gunk in the lines, that somehow worked its way to the cylinder.
Thanks again, and I will post in the future if problems persist.
If it is a problem with crud in the master cylinder is there a good way, other than taking it completely apart, to clean it out?