I got a part in .igs formate after converting the part i got a assembly in the for of .sldprt which contains 12 surface bodies and 100 solid bodies which I need to separate and do the drafting of the parts. But I am unable to separate the. I tried for various methods but in the end its  useless

1) Isolating each part and separating them and saving them but if I will come of from the isolation it be the same 

2) split is not working on the part properly

3) I switch the file in para solid then used the split function I got a result but half of the prt is is missing or its not coming in solid form

4) deleting the parts one by one but in the tree I am getting a option of deleted bodies if I try to remove them the parts a coming back

please let me know the best way to overcome from this situation 

Edu ​​​​​​​