The groove blocks are made of silicon, which is a brittle material. Do not handle them using metal instruments. 

Each groove block is carefully inspected, cleaned and packaged before shipping. However, dust may settle on the polished surface once the protective cap is removed. Users must therefore inspect the product. Use of a 400x microscope is recommended. 

1. Wet a cotton swab with a 1:1 blend of 99% isopropyl alcohol and acetone. Sponge off the excess liquid with a wipe intended for delicate tasks.
2. Gently pass the cotton swab over the block’s polished surface, in one direction only. 
3. Quickly wipe the surface with a dry cotton swab.
4. Inspect the surface of each fibre again, and repeat cleaning as needed. 
5. Align the block then fix it in place with an appropriate adhesive. 

Before you inspect a connector, always make sure the light source is turned off.