code: function claimBackOldTextcoins(to_address, days){
  	db.query(
  		"SELECT mnemonic FROM sent_mnemonics LEFT JOIN unit_authors USING(address) \n\
  		WHERE mnemonic!='' AND unit_authors.address IS NULL AND creation_date<"+db.addTime("-"+days+" DAYS"),
  		function(rows){
  			async.eachSeries(
  				rows,
  				function(row, cb){
  					receiveTextCoin(row.mnemonic, to_address, function(err, unit, asset){
  						if (err)
  							console.log("failed claiming back old textcoin "+row.mnemonic+": "+err);
  						else
  							console.log("claimed back mnemonic "+row.mnemonic+", unit "+unit+", asset "+asset);
  						cb();
  					});
  				}
  			);
  		}
  	);
  }
docs: if a textcoin was not claimed for 'days' days, claims it back