Have you ever use a script? Here's one that will do what you want. Copy and Paste into a text editor and save as a .jsx file (plain text).
#target illustrator
// deletes pathItems smaller than the supplied length
var idoc = app.activeDocument;
var howLong = prompt ("Enter the size in points of small paths to be deleted", 2, "Delete Small Paths");
for (i=0 ; i< idoc.pathItems.length; i++)
{
var ipath = idoc.pathItems[i]
if ( ipath.width < howLong && ipath.height < howLong)
{
ipath.selected = true;
}
}
app.redraw();
if(confirm ("Proceed to delete selected items?", "yes", "Confirm Delete"))
{
app.cut();
}
