I bought a pump version of scrubbing bubbles and emptied the contents into a rubbermaid container with a snap on lid. The container is tall enough, and holds enough scrubbing bubbles, to cover the DE completely. I toss a grungy one in there and let it sit for five minutes. Rinse throughly under the tap. I once left a German slant in the soup too long and it took the plate off of it. That is when I started going no more than 5 minutes. Some guys drop TTOs and adjustables in mineral oil to throughly lubricate them and I have done that on occasion.
Gold plated DEs are best cleaned with Windex from what I've read. I've done that on the rare occasions when I've had one to clean and it seemed to be fine. Did the job and didn't hurt the gold plating. There may be other ways to go about it but I am not aware of them.
BTW, the slant that lost the plating was probably made right before, during, or after WWII. The base metal appears to be zinc or some such. The plating was probably not of a quality of a Gillette or the like.