Bottom pour I’m guessing with temp knob on top? If it were me I’d put the pot on a surface outside of the living quarters, get a cheap small muffin pan from the store, heat the pot up on 6-7 assuming there is lead in it. DO NOT get any water in the lead!!! Once hot drain lead into muffin pan holes. Wear leather gloves trust me! Unplug let it cool.
With or without lead, take screws loose that hold the plunger and remove plunger. Scrub inside pot and plunger with wire brush and steel wool to remove rust and scale. Make sure the divot in the pot where the plunger seats is good and clean. I’ve had to scrape around in that with a flat screw driver before. Just go easy. Refill the pot with lead and heat it up. Never run the pot on empty. I usually try to keep mine half full to minimize rust. Be forewarned, it’s a Lee pot it’s gonna drip some even perfectly cleaned.
I should tell you here to use pure soft clean lead to refill. I would be a hypocrite if I did. Hard dirty lead like wheel weights are a booger to pour but doable. I just flux mine good in a junk cooking pot on a camp stove outside with a small chunk of wax to get the junk to come up to the top and skim off. Caution this will briefly cause a lot of toxic smoke and a small fire in the pot but it will burn off. Soft lead pours much better. The lead sinkers should do just fine. It’s whatever you have access to that has worked for me. As far as temp I pour most of my 1/4 oz jigs on the #4 setting. Some molds like it a little hotter 5-6. Again, this is just my take on it.