# Sandbox.SandboxSystemExtensions.RemoveBadCharacters

```csharp
static string RemoveBadCharacters(string str)
```

Removes bad, invisible characters that are commonly used to exploit.
https://en.wikipedia.org/wiki/Zero-width_non-joiner

### Parameters

- `str` (`string`)

### Returns

`string`

Declared in [Sandbox.SandboxSystemExtensions](/api/Sandbox.SandboxSystemExtensions).
Assembly: `Sandbox.System`.