Take some deep and straight standing shells, fill them with melted wax, place wicks with holders into the bottoms and let them dry. You can pick up a block of wax and a bag of wicks at your local craft store. Also consider recycling some of your candles! I always have quite a bit of wax leftover from my pillar candles. The deeper the seashells the longer your seashell candles will burn.
Picture via Pottery Barn.
Learn how to Transform Large Seashells into Candles at BHG.
And another Seashell Candle Project posted on BHG.
Shell Candles at Martha Stewart.
Also via Martha Stewart. To add glam to your seashell candles, spray shells first with metallic paint. Pour the melted wax into the shell, then place a wick and holder in the bottom of the shell!
How to Make Seashell Candles at Country Living.
And for detailed instructions, plus a video to watch go to Martha Stewart.
Spread a warm beachy glow with homemade seashell candles!
You might also enjoy this DIY Oyster Shell Candle Holder.