public/Get-AsciiString.ps1

function Get-AsciiString {
    <#
    .SYNOPSIS
        Trim leading and trailing spaces from string, and optionally replace non-ASCII characters
    .DESCRIPTION
        Trim leading and trailing spaces from string, and optionally replace non-ASCII characters
        such as diacritic characters with corresponding ASCII characters
    .PARAMETER String
        Required. String value to be trimmed and cleaned.
    .PARAMETER Cleanup
        Optional. Replace diacritic characters with ASCII characters
    .EXAMPLE
        Get-AsciiString 'diakritikós '
 
        returns 'diakritikós' (trailing space removed)
    .EXAMPLE
        Get-AsciiString 'diakritikós ' -Cleanup
 
        returns 'diakritikos' (trailing space removed, and ó is replace with o)
    .LINK
        https://github.com/Skatterbrainz/helium/blob/master/docs/Get-CleanString.md
    #>

    param (
        [parameter()][string]$String,
        [parameter()][switch]$Cleanup
    )
    if ([string]::IsNullOrWhiteSpace($String)) {
        ""
    } else {
        $result = $($String).Trim()
        if ($Cleanup) {
            $result = [Text.Encoding]::ASCII.GetString([Text.Encoding]::GetEncoding("Cyrillic").GetBytes($result))
            $result = ($result -replace "'","") -replace '[^a-zA-Z0-9\- \.\,\;\:]', ''
            $result
        } else {
            $result
        }
    }
}