What is the proper application of liquid borate treatment(such as Bora-Care)to window sash?

1) Should it be painted over the entire bare wooden sash? 2) Should it be applied to open endgrain for maximim penetration? 3) Would allowing edges(rails & stiles) to soak in it for a few minutes be all that is necessary? (application to susceptible areas) 4) Will applying to entire sash have any adverse compatibility with other materials such as the putty, linseed oil, paint etc? 5) From my research, borates contains salt. On later sash where metal pins are used, could this cause corrosion? How about corrosion of the glazing points? In some older sash hand wrought nails were used, would the salt have any effect?

Any help will be apprecited.

I didn't find the right solution from the Internet.

Online video production

Thank you.