The other day I ordered an Olicamp hard anodized aluminum Space Saver cup from Amazon using some points. It arrived today and I think it'll be a good piece of gear. It's lightweight and has graduations so that you can use it for measuring water.
One thing it lacks, however, is a lid, which means that if you use it as a pot to cook or boil water in, it'll take longer and use more fuel. I've used expedient lids made from aluminum foil in the past with my GSI stainless cups and USGI canteen cup. I wanted something better for this cup.
My first try was made from aluminum flashing. I traced the lip of the cup on a piece of scrap wood to create a form, and cut a piece of flashing a bit larger around than the cup. I then secured the flashing to the form and pressed it around.
It looked like ass.
In search of a better solution I ran across this video by IA Woodsman, in which he made a lid for a stainless GSI cup from the bottom of a 12 oz. coffee can. I had an empty can so I went back out to my shop and made a similar lid.
The lip of the aluminum Olicamp cup is a little larger in diameter than the stainless GSI cups, so I cut eight small slits around the edge of the lid so I could spread it out to better fit on the cup. Instead of IA Woodsman's copper D-ring, I used a stainless steel split ring from my scrap box. Click on the picture to see the full sized version which shows how it can be set so that it doesn't flop over.
The ring is secured using a similar tab to IA Woodsman's. However, I used a stainless screw and nut instead of a rivet.
I'll probably carry the cup nested over the bottom of a 32 oz. Nalgene or 40 oz. Kleen Kanteen bottle, with the lid in the bottom of the pouch.