What a great tip and do enjoy your voucher - I love to get the sales with anything like that - so I get more for the buck - so to speak.
Congratulations! Good Idea. Mine is also clear.
For those with slow internet her tip is:
From Terese: The bobbin cover on my machine is transparent and when I lay it down on the table, I have a hard time seeing it when I want to replace it. So I put a dab of bright nail polish on it and now it is easy to spot.
Congratulations! If your decision on what to do with the certificate is TOO tough, just send it to me!! LOL
Angel