Lanyards are one of those things that you can't often bear to throw out because of some sentimental reason or other, so they tend to accumulate into large tangled heaps. Here's one attempt at recycling them into something useful, by turning them into dog collars.

This instructable shows how to make an adjustable dog collar from a lanyard.

Step 1: What You'll Need

Materials needed

A lanyard. These come in various widths but generally tend to be about the same length (around 75 cm or so). Pick one that's fairly wide as this will be the width of the collar, you don't want a thin strip that cuts into the dog's neck.
A plastic side release buckle. Some lanyards, like the one shown here, come with one.
A D ring. Lanyards generally come with a circular ring although some come with D rings.
A strap adjuster.

The last three items can generally be salvaged off old backpacks, pouches and the like.

Tools needed

Scissors, or utility knife
Lighter
Needle and thread, or sewing machine

Safety considerations

Points and Sharps (cutting the lanyards and sewing)
Fire (melting the ends of the lanyards)

Time required
About 15 minutes once you've gathered all your materials and tools.

Step 2: Cutting Up the Lanyard

Cut up the lanyard, getting the longest length you can and keeping any necessary parts.

If you're fitting the collar to a specific dog, measure the dog's neck size (circumference) and add another 15 cm (6").

Trim the long lanyard piece to the desired length.

Step 3: Seal the Ends

Run the flame of the lighter over both ends of the lanyard to melt and seal up any frayed ends and loose threads.

Step 4: Adding the Strap Adjuster

Slip on the strap adjuster onto one end. The front facing side of the strap adjuster and the printed side of the lanyard should be oriented. If you're using a lanyard printed on both sides, the orientation doesn't matter.

Step 5: Securing the Strap Adjuster

Fold the end of the lanyard over and sew it in place (by hand or machine). Use a few rows of stitches for reinforcement.

Step 6: Adding One End of the Buckle

Slip on one side of the buckle (it can be either the hook or the catch end of the buckle). If the buckle has a forward-facing side, make sure that it corresponds to the forward facing side of the lanyard.

Thread the lanyard through the strap adjuster.

Step 7: Adding the Ring and Other Side of the Buckle

Slip on the D ring on the free end of the lanyard, followed by the other side of the buckle. Again, note the orientations of the ring and buckle relative to the lanyard.

Keep about 5-8 cm (2" - 3") of the end of the lanyard free.

Step 8: Securing the Ring and Buckle

Sew up the folded section of the lanyard, to keep the D ring and buckle end in place. Again, use multiple rows of stitching to ensure a secure attachment.