Tablecloth Clips – How To Prevent Rust?

I enjoy camping, but am a little bit of a neat freak so for me it’s a necessity to have a vinyl tablecloth to put on our picnic table when we go camping. I use inexpensive, supposedly rust resistant, steel tablecloth clamps like these that are available from Camping World but mine rust after only a few uses which creates unsightly stains on my tablecloth that I have a hard time getting rid of.

I’ve tried coating the clips in clear fingernail polish but it wears off really fast.
I also tried some plastic ones that I found at my local dollar store but some of them broke the first time I used them.

I end up replacing my tablecloth every year because I hate how it looks with the rust stains on it.

Today, I came across these Camco Tablecloth clamps . They’re not supposed to rust at all – instead of being rust resistant they’re rustproof, but the downside is they cost about $10 for 4 of them versus the rust resistant ones that I get in a 6-pack for less than $2. I’d need two packages of the Camco ones.

I’m wondering if anyone has used these and if they’re worth the money?