If I'm not wrong we can't change a glob key/element, only access it. Soo, this won't work:

undef *{$glob}{$type} ;
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And I make this:

if    ($type eq 'SCALAR') { undef ${*{$glob}} ;}
  elsif ($type eq 'ARRAY')  { undef @{*{$glob}} ;}
  elsif ($type eq 'HASH')   { undef %{*{$glob}} ;}
  elsif ($type eq 'CODE')   { undef &{*{$glob}} ;}
  elsif ($type eq 'IO')     { close *{$glob} ;}
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Not to remove the element from the GLOB, but to ensure that it goes out of the memory, since undef *{$glob} already remove all the keys/elements. Actually for your needs you can remove all the if ( $type eq '...' ).