how long does it take for crystal meth to completely leave your system?

after 10 years of daily use, how long does it take to have the crystal meth completely leave the system
is necrosis part of the long term effect from this Poison
if a toxicology screening is taken, how long after use would this be apparent

: http://alcoholdrugstreatment.info/how-long-does-it-take-for-crystal-meth-to-completely-leave-your-system