roots clinging to clay pot

[fredr]

Hi,
I read somewhere that phals will not cling to plastic pots. Don't know if that is true or not but I'd like to repot mine from clay to plastic as their roots do climb all over the clay pots. I also read (whereever) that one should soak the pot in water to soften to roots to get them lose. My question, how long should I soak them? By soaking I guess it was meant to sink the pot into water from some length of time. How long?

Fred
PS I'm putting white packing peanuts into the bottom to asure drainage and will then add a phal bark mix as new medium. I'm sure my old lava rock is saturated with salt.