I assume this is PAINTED moulding? Using a nail punch can be tricky. You have to find the right sized nail punch to properly sink the nail. If the punch is oversized, it tends to slide off the nail. If it's undersized, there's usually not enough force to punch the nail in properly.
Any gaps that are more than a 1/4" wide will not hold caulking very well. So, as long as the gaps aren't big, you can fill them with a flexible caulking. I use MaxFlex from SW but there are similar versions such as Big Stretch, etc. Keep a damp cloth handy to smooth out the caulk and remove any excess. Let it dry and harden up for 24 hours before painting.
Nail holes can be filled with spackling. It shrinks, so you will have to fill it more than once. Sand off any excess, prime the area, and paint.
Gaps around the ceiling USUALLY disappear once spring comes and brings in more humidity allowing the wood to swell and return to position. In winter, it's so dry the wood shrinks ever so slightly causing rafters, joists, framing to move enough to create a gap. Filling those type of gaps usually doesn't work because when the wood swells and moves back it pushes the caulking out of the gap making an ugly glob of dried latex caulking.
Any gaps that are more than a 1/4" wide will not hold caulking very well. So, as long as the gaps aren't big, you can fill them with a flexible caulking. I use MaxFlex from SW but there are similar versions such as Big Stretch, etc. Keep a damp cloth handy to smooth out the caulk and remove any excess. Let it dry and harden up for 24 hours before painting.
Nail holes can be filled with spackling. It shrinks, so you will have to fill it more than once. Sand off any excess, prime the area, and paint.
Gaps around the ceiling USUALLY disappear once spring comes and brings in more humidity allowing the wood to swell and return to position. In winter, it's so dry the wood shrinks ever so slightly causing rafters, joists, framing to move enough to create a gap. Filling those type of gaps usually doesn't work because when the wood swells and moves back it pushes the caulking out of the gap making an ugly glob of dried latex caulking.