@Claribel8 I do find evidence that my guests have eaten in their private room, even though they have full use of my kitchen. Mostly snacky stuff like cookies, an apple, etc, which I see the remnants of in the waste basket. But I've never had a guest eat anything messy in there and stain the bedding or towels. If you don't allow kitchen use, then guests will be more likely to eat more major food than a piece of fruit or a candy bar in their room, but I'm not suggesting you allow it, many hosts have found that problematic, altho my guests have always cleaned up after themselves well in the kitchen.
Is there any space in your private room for a small bistro table and a chair or two? (there isn't in mine) If so, maybe try that, with a request to guests (a nicely framed note in the room, perhaps) that they eat at the table, not in bed, as you'd like to avoid having to charge them for stained linens. A bit of scare tactics might lead to compliance 🙂
And search for threads here, as well as google, on stain removal techniques. Most stains can be removed if you just know what to use on them. Whatever you do, don't wash anything that looks like it could stain in hot water, that just cooks the stain in so it will never come out. Throw them in cold water-sometimes that alone does the trick, then move on to stain removers if needed.
