I tried to replace a wick the other day but, seems impossible lol, got a lot of used top coils saved up never been able to find good instructions
Its a bit of work but 1 method is to tie some dental floss around an end of the new wick, tight. clip wick as close to the dental floss knot as possible. Slip other end of dental floss through a large sewing needle and pass needle through coil and pull wick through.
I'm at about a 50/50 success rate. When I found new coil wicks fo $.99 each I quit trying.
I use long wicks, After a cleaning or two and I have a black spot I can't remove, I slide the spot out which leaves a clean bit in the coil. works almost like new. I can do that a few times. Coils last multiple weeks. My longest use was 47 days until the coil actually broke. Not bad for 99 cents.