There are 2 Slime products

Tubeless -- & Tube type.

NEITHER I have used are pressurized containers.

I had a flat on the front of my 255 Ferguson MAY. 14. I put half a bottle of Slime in it THEN aired up to 35 psi.
Tube type
YES put hole/leak on bottom THEN add slime. Give it a little time to seal.

Still Holding today.

[Linked Image from i.imgur.com]

jwall- *** 3100 guy***

A Flat Trajectory is Never a Handicap

Speed is Trajectory's Friend !!