Constant Tire Leak - Thru the Casting?

[mountaineer2004]

One of the aluminum wheels on Mounty has been leaking a couple of pounds a month for at least 10 years.
Through new sets of tires and all, even after I tell them to clean that wheel extra well.
I just live with it and refill when necessary, although I've marked it to keep track of it after tire rotations and such.

 

[410Fortune]

I wonder if slime would help? I know not the best thing inside a tore but there are some good ones on the market. I use tireject for troublesome atv/utv tires stuff is golden