I'm sure others already use something similar, but i came across some cheap little refillable pens with brushes that I filled with gun oil. They easily get into tighter places like around trigger assemblies, rails, etc., where you usually have to spray or drop oil to get to it. Much more precise than an aerosol can or drops. $7 for 5-pack on Amazon, or you can get em for less than $1/ea on Temu. Search for Oil Cuticle Pen.