Massachusetts government is sort of like the individual who reaches into the pockets of a long-unused pair of trousers, or into an old purse, and finds a forgotten twenty-dollar bill.
It's not that the state Department of Revenue didn't expect to make something from the amnesty program for tax dodgers it initiated a year ago. It's that the payoff apparently is going to be larger than anyone anticipated.
With the final chapter of the tax-amnesty story nearing completion, Revenue Department officials, most of whom originally were anticipating a total yield of no more than $10 million, now expect the final figure will be eight times greater.
Already in hand is some $71 million. And by the time the last check is received and tallied the commonwealth may have another $9 million.
There's just one catch: Like the individual who goes out and ''blows'' the $ 20 bonanza instead of adding it to his or her savings account, the state has already spent most of the amnesty money.
That the ''once in a lifetime'' opportunity for tax evaders to voluntarily come forward and settle up with the state was a good idea is evidenced by the 46 ,951 applications for amnesty received during the 90-day grace period from Oct. 17, 1983, to Jan. 15, 1984.
Handling all the paperwork, however, has taken a lot longer and proven considerably more complicated than had been anticipated.
In many instances the amounts owed, or what various delinquent taxpayers thought they owed, covered several years. Sometimes no individual or business tax returns had been filed on the income involved.
Obviously, there was no way the Revenue Department could accept, without verification, what amnesty applicants said was due. Even when the amount evaded is correctly stated, there is the question of add-on interest which must be computed.
Still unresolved are some of the more complex cases in which those who have come forward, either to clear their consciences or avoid later being caught, are in disagreement with tax officials as to how much they owe.
Others, although acknowledging their obligation, have not fully paid up or have had their checks caught up in a processing backlog within the Revenue Department's amnesty unit.
The latter situation, involving 368 uncashed checks, has considerably disturbed state Rep. William G. Robinson (R) of Melrose, the House minority floor leader. In a letter to state Treasurer Robert Q. Crane which the legislator made public, he suggested that delays in depositing amnesty receipts may be in violation of Massachusetts law.
This charge could hardly be ignored by the administration of Democratic Gov. Michael S. Dukakis.
Whether the Robinson criticism is the ''tempest in a thimble,'' as it was described by state Revenue Commissioner Ira A. Jackson, any delay in depositing checks, no matter how few, is unjustified.
It should be noted that approximately 150 of the 368 unprocessed payments from tax evaders or delinquents, as of Oct. 9, had been in hand for more than two weeks.
While it is questionable how much potential interest may have been, or still may be, lost through delays in deposits, the Commonwealth clearly needs every dime it can scrape together. This was underscored by Governor Dukakis in his recent warning that an additional $600 million will be required in the next fiscal year to maintain state programs, including local aid, at their current levels.
Some of this new money will be needed to fund programs paid for this year by the ''one-time-only'' amnesty windfall, which produced $67 million in fiscal 1984, the year that ended last June 30, and is expected to amount to $13 million in fiscal 1985.
Clearly it was a mistake - perhaps one of significant proportions - not to have somehow set aside all of the amnesty money for some special, nonrecurring project, such as construction of a major building, or to have placed it in a trust account to produce funds to support some program such as scholarships at state colleges and universities.
State lawmakers, including Mr. Robinson, could have initiated such an arrangement in the absence of leadership in that direction from the Dukakis administration.
Another quite possibly very good use for the amnesty money might have been for establishment of a much-needed, long-overdue ''rainy day fund'' to be invested and held in escrow for use when annual state revenues in economic hard times fall far short of what is required to maintain essential public services.
The absence of such a nest egg, even one of modest dimensions, could result in burdensome tax increases should a serious funding emergency face the commonwealth.
Lawmakers in at least a dozen states, including California and Michigan, have in recent years provided such fiscal umbrellas for their governments.
In some instances a specific portion of the revenue growth each year is automatically earmarked for the emergency fund, which can be invaded only under certain situations, including an unexpected major shortfall in the total tax yield due to economic hard times.
As unattractive as this type of restriction may be to Beacon Hill spenders, it certainly is not too late to set up such a special separate account to use as a hedge against the possible threat of another round of tax boosts.
Legislation could be passed to set aside whatever the amnesty program brings in during its remaining few weeks, as well as the approximately $4 million collected since last July 1. It might even be possible, with a bit of rare frugality, to somehow come up with $67 million to make up for amnesty money collected and spent or committed for state general-fund purposes between last January and June. This would tend to make the amnesty program a more lasting success - one taxpayers could view with pride and some relief.
Instead of calling for various tax sweeteners, such as increased deductions for certain citizens (as politically popular as such gestures might be), Massachusetts lawmakers might spend their time better coming up with something which would benefit all taxpayers by shielding them from future tax hikes.
An $80 million reserve may not look like much in a state with a current annual operating budget of $8.1 billion, but it could be a significant start in the right direction. If invested and the interest kept in, it could grow perhaps appreciably over the next few years.