Fram,Its pritty much the way I go about it.I use washing powder and leave it to soak,as long as its not water proof pva/wood glue.These tend to grab the pore's in the surface of the resin.
As for temp. Handwash warm.Any warping can be reversed with a little reheating and repositioning,
Any warping that didn't happen in the mould can be corrected.That said depending on how you intend on triming down the bases,leaving the pva on might be a blessing,then only remove the pva thats left after triming.It could reduce the risk of damage to the section you intend to keep.
Mark.