Halloween paints are still working.
There is a program called TFMV which lets you preview loadouts and paints on TF2 classes by scanning the VMT files for each item and making an easy interface for editing them (then loading them in HLMV), but it (somewhat understandably) doesn't include any of the Halloween paints.
I read this wiki page about previewing paints by editing the color values in the VMT files for each item, but it doesn't mention how the Halloween paints animation worked or what their color values were.
If anyone knows what the values are that need to be edited in an item's VMT file to see a Halloween paint, or any other way I could preview this effect, please help
P.S. I want to view the effect on a specific item, so the preview on youtube of the paints on a gibus is not helpful