I don't have much experience with paddle beaters. Mostly double whisk attachments. This advice is based on my experience.
If you intend only to clean most of the material off of it;
I'd suggest first removing the attachment and then shaking the bulk of the mixture off. Shake down into the bowl as gravity/inertia are your best friends here.
Then, using a ...
I replace the bowl with a clean, high sided bowl, and turn the mixer on high. The blades throw everything off into the bowl. Then it's easy to scrape that out. I often end up using that bowl for something else anyway, so there's no extra washing.
Use a rubber spatula to scrape the mixture off one side of the paddle. (For a head lift mixer, do this on the "uphill" side.) Them use the spatula diagonally in the holes, pushing the remaining mixture through the holes onto the unscraped side and off the paddle. The idea is for the mixture to fall out/off in clumps.