As someone else noted, these things really should come with a dew shield.
Note the safety cover. That came from a 48 oz grapefruit container. Since I go through one every ten days or so, I can afford to experiment with them.
For the cone: one empty potato salad container.
Step one is easy, a small slit with a razor knife around the base to prevent cracking followed by a little scissor work.
To cut a ring from the grapefruit lid, I drilled a hole in the center, and used that to cut the correct circle with a stand mounted Dremel.
Test fit and scuff the surfaces for painting
Problems:
1. I don't have any glue that adheres well to polypropylene.
2. My can of chalkboard black lost pressure
Solution: Flex Seal (as seen on TV) or any similar product. It will stick to most surfaces and will craze polypropylene so that other coatings and adhesives will stick to the new surface. It also makes the outer surface easier to grip with gloves on. The only downside is that it produces a fairly coarse spray and takes up to two days to cure. It took me a week to get the degree of coverage I wanted inside and out.
Note: I left the underside uncoated to prevent it from gripping too tightly, It already fits snuggly enough to twist off the front retaining ring of the
Test fit.
Ready to Rock-n-Roll
The rubbery coating is not very reflective but if it turns out to be an issue I can easily add a coating of chalkboard black to the inside.
[Disclaimer: At no point did the cat actually contribute any effort to this project.]