One of the little items I've used in the past for a multitude of photographic applications is Cinefoil. It's almost a standard within the film industry, and while a roll of it can set you back a little, it can be re-used over and over again, re-shaped, and it will hold shape. It take a fair amount of use for it to wear through.
You can find it on eBay and Amazon, but here's a link to an Aussie supplier.
https://www.productionshop.com.au/cinefoil/
Cheers.