at low revs manual transissions do make rattly noises ...dont do it. Use the clutch so that the transitions to power /no power are made smoothly with as little trauma to the driveline as possible.as sonnas you feel any roughness in the driveline its time to change down or push in the clutch(if you are already in first).In slow traffic dont try to drive slower than idle in first by slipping the clutch for long periods,but go at idle in first for a bit then stop then idle in first.....