Japanese Thread : Synthetic non-tarnishing gimps available in Gold, Silver and Copper.  These threads are excellent for fine stitching, outlining, couching, and laid work.  They give the appearance of stitching with real gold, silver or copper.  Since real metal threads are rare and expensive, Japan Threads are an ideal substitute. They are dry-cleanable only 

Left to right - Copper  Gold  Silver Weight#7

Dark gold was missing on picture taking day.

To open a skein of Japan #5 or Japan #7, hold the skein by the loop with one hand and gently pull off the paper label. Hold the skein and insert one or two fingers into the loop end that does not have the knot. Separate the twisted threads by running your finger slowly down the middle and gently pulling them apart. Lay the skein on a table and untie the loose knot located at one end. Insert your finger in the loop at the end opposite the loosened knot. Place your other hand in the center beneath the loop and very slowly separate the twisted threads. Cut the threads at one end and then use the appropriate length for your stitches. The remaining Japan Threads should not be folded.