1992 Other Saturn Models white soapy bubble in the radiator

Hi. I have a 92 saturn 4 door auto that I just bought for my niece. The car runs great does not over heat, and the is no smoke. I was about to change the radiator fluid and fount a white soap like with bubbles in the radiator. I dont know if these is normal would getting it profesionally flush will take care of the problem? Any help would be much appriciated. Thank you.