When working in a development environment you’re bound to get it dirty or someone else on the team make major refactoring’s. You need do clean up and make a clean deploy. Here’s a simple way to retract and un-install all SharePoint Farm Solutions using PowerShell (haven’t tried this with sandboxed solutions).

Retract All

Get-SPSolution | foreach { Uninstall-SPSolution -Identity $_.Name -Confirm:$false -AllWebApplications }

Remove All

Get-SPSolution | foreach { Remove-SPSolution -Identity $_.Name -Confirm:$false -Force }

That’s it