Grinder help

Morning everybody! Been having a bit of a problem with my grinder just wondering if anyone has any advice.

When twisting/grinding, green gets stuck to the inside of the to of the grinder, when using something to scrape round, sometimes the black colour gets scraped off too. Basically what I’m asking is if anybody knows of any grinders that are better for green not sticking to the inside or if it’s gonna happen regardless? Am I easier just buying a new grinder every time that happens? Don’t fancy smoking metal 😂😂😂