Drive not working properly

My sony rx320ee drive is not working properly.Sometimes it gets jammed i.e-when i press the button to open the drive it does not opens some times(not every times),instead it makes a noise like cut-cut.But it closes normally.And another problem is that it ignores reading some DVD's.but works well with others.It reads all the CD's well.I think its getting dirty,am i right or its tray needs some oil.Pls help me.