" Quite simply, I might say: "I need to get rid of that tick that's been biting me all day." I would not say: "I must be free from that tick." And that is why I might use "rid of" with a chilly, instead of "free" (it does not matter https://energygrants.finance.blog/2024/08/21/how-to-apply-for-solar-panel-grants-scotland/