How to finish off a silicone sealant like a professional

I've used a craft knife to cut out most of it (being careful not to damage the surface), then a small (2") putty knife to scrape out the rest. Nylon scrubbing pads (the ones made for cleaning non-stick cookware) are great for getting rid of any last traces of the old caulk.

A chisel would work, but chisels are supposed to be very sharp, so I'd be very careful not to scratch whatever surface the caulk is applied to. A putty knife isn't as sharp so it would take more work on your part to do any damage.

There are two primary uses for caulk:

1. aesthetic gap filler
2. functional moisture/air barrier

For the latter, you'd see that wherever you need to waterproof joints (shower panels, exterior windows, etc.)

For the former, it can really be used in any situation where you have two pieces of material meet. Typically this is done when two different materials meet and you want to cover a small gap. Example would be where door trim meets the sheetrock. Higher end finishing would have that caulked before painting.

So, as for these shelves, it's really up to you. One option is to caulk it. Another would be to attach some trim moulding.

As for how to properly caulk, the basic method is:

• cut tip to size
• apply to joint
• smooth to finish

There are tools to smooth it, but I prefer to just use a wet finger (and plenty of paper towels to wipe finger off as you go...)

Note if the gap is too wide, you may need to fill the gap first. I've used foam weather stripping in the past for this.