I have been noticing dirt like particles coming out with semen. they are hard and brownish. is it a problem? what should i do to remove them?

There can be various reasons for semen that semen appears " clumpy" or has particles. Sometimes it is just sperm cells or other dead cells that are building up in the semen and sometimes it could be a result of other conditions like inflammation or infection. It may be best for you to see your regular doctor and perhaps a urologist for an evaluation.