VETSCOPE

My cat goes outside and sometimes comes back with ticks. It's easy to remove 1mm size ticks, but bigger ones around 3mm bite onto the skin firmly and won't come off. Is there a good way to pry them off? I've tried skin drops on the neck, drugs you use on blankets and the body, and a collar - he tore it off in a few hours while he was outside. Please give me advice.