Can you ignore noisy valve lifter

CAn you ignore noisy valve lifter, or do you have to do something
to avoid real engine damage. Problem is intermittant, on a vehicle I'm thinking of buying.

Make sure its a lifter and not a rod, with the engine running get down under it and get your ear near the oil pan DRIVERS side, if it's louder down there than up top it might be a rodbearing. Other than that noisy lifters can usually be cured with a good engine cleaner flush for fast results or running a high detergent oil that will clean them out. They get noisy because the are not filling up with oil right away due to crud buildup, when the engine oil is cold and thick it can't get past the sludge, once it warms up and thins out it works it's way in there and fills the lifter. Replacing the lifters requires that the head be pulled so trying to clean them first is a better idea.
If you do pull the head thats also a good time to get the valves done, cuts down on the labor charge a bit.

What do you mean by a "good engine cleaner flush"? Are you referring to something like GM top end engine cleaner?
Thanks

On another post further up I mentioned four ways to clean out the insides, first is with an engine flush, usually sold in quart cans that you dump into the oil and then run according to directions, some oldtimers used ATF or Kerosene. Not my cup of tea using ATF or kero.
I prefer the long haul approach of using a good synthetic oil and allowing its high detergent properties to clean the passages and sludge out. Takes longer, maybe two or three oil changes.
One method that I did try was with a snap-on flushing machine, we did not get much out of mine because I have been running Mobil-1 since around 5,000mi of it's 192,000mi life but I did see a couple of others flushed that were much newer than mine, a benz and a Pontiac firebird that got some pretty nasty stuff out compared to mine which only discolored the toilet paper roll sized filter that the machine uses.
One thing to check, the injectors on the 4.0L in the XJ and the 2.5L that we have in our TJ are friggin noisy but these are the first MPFI vehicles we've had and from others I have listened to thats normal. I'm just curious how often MPFI clacking is mistaken for noisy lifters cause the first time I listened I thought it was lifters also. I finally convinced myself after using a stethescope that it was in fact the injectors, just something to keep in mind.

How much did you pay for the flush Rich? I haven't seen that offered down here in JAX, FL. Do you think it would be worth the $$?