this topic has been covered in great depth elsewhere, no its not as easy as tighten the bolts and nuts because its a poor deisgn to begin with.
My solution was to remove them, as I type there sitting here next to me.
The new problem being their more of a bash plate protection shield then a heat shield and Im worried about damaging the exhaust pipe now, so Im going to source some high temp exhaust wrap (off ebay about 80 bucks) to wrap around the exhaust first then re-bolt the shields back on
The usual reason they rattle is because over time they fill with
small stones etc.
10 metres of exhaust wrap (5 per side) will do the trick.
Make sure you replace old material.
Easy to remove, get under the car and have a look!