The usage of 的 at the end of the sentence
To perform the meaning in the given context below sentences would be useful: 


  1.我衣服洗得很干净   (100% perfect correct, native chinese , popular sentence )
  
  2.我衣服洗得很干净 (的)/(滴)/(啦)/(哟)/(呐)/(呀)  etc...
  ( only to emphasize, no additional meaning. )
  
  3.我洗(过)(的)衣服很干净  (native, perfect,popular )
  
  4.我的衣服洗得很干净 (native,perfect,popular, 4 is the full sentence of 1)
  
  5.我洗衣服/很干净的  ( olny a bit weird but most ppl understand)
  
  6.我洗衣服(的过程)是很干净的 (native,perfect,popular, 6 is improvement of 5)


if you only want a shortcut, following the most popular way native speaker says will be more useful than researching on Chinese grammars stuff.