"If you don't have a system for collection, the aging receivables will bury you," says Donald J. Long, president of Imperial Inc., a wholesale supplier of fasteners in Green Bay, Wis.

Strict credit policies have enabled Imperial to hold the line on accounts receivable at 40 days. A computer is used to take weekly readings on the aging of accounts. The first collection letter goes out at 30 days, the first phone call on the 45th. If payment has not been made 60 days after the billing date, a hold is placed automatically on all further shipments.

Imperial's system may sound harsh, but one experience with a softer policy was enough to prove the value of discipline. When the company cut out its 30-day notices for a short period, collection time slid up to 44 days.

Management of accounts receivable cannot be done by formula. What works for one company may not work for another. There are, however, some general tactics that can prove helpful:

* Make sure that billing takes place at the time of shipment. A lag in paperwork can hold up collection almost as much as slow-paying customers can.

* If you establish a policy, stick to it. Customers soon learn to recognize empty threats.

* Personal contact can sometimes speed response. If the situation warrants, be prepared to handle some collection calls yourself or to press salespeople into service in cases where there is a long-standing relationship.

* Negotiation may be preferable to an unbending stance in cases where the customer seems in danger of foundering. If you push your debtor into bankruptcy, chances of recovery may be nil.

* Consider the size and activity of the account when setting terms. It may pay to be more lenient with large customers.