term clarification.
"blow by" is when the rings are worn to excessive gap or stuck in the ring grooves not allowing them to expand against the cylinder walls, or cylinder walls are scored/gouged allowing compression pressures to "blow by the rings" into the crankcase...oil becomes prematurely black with carbon abrasive and piston skirts show signs of carbon build-up.
oil on the external engine is a leak...not "blow by"... per se.
it can come from anything from a clogged PCV system to a faulty gasket, to a cracked block or head.
in the first case, it's compression pressures, in the 2nd, it's downward piston pressure. a compression test can show low compression indicating "blow by", if the numbers are good it's a breather problem... if the internal engine shows carbon it can be a blocked passage. since the EPA got involved, they generally use the intake vacuum to draw a slight vacuum on the crankcase.
you can squirt a teaspoon of oil on the pistons and if the compression numbers improve, it suggests rings not sealing
"thing-a-ma-jig" and "doo-hicky" are not exceptable in any case to mechanics...there's a universal extra charge for mis-use of terms by the illiterate... and we have a zero tolerance policy.
if you have compression pressures in the crankcase and actual "blow-by, then you need to address the rings and mic the piston skirts/cylinder bores...there's no other fix.
mystic marvelous clearance clogger additives are not acceptable unless your intent is to pass the problem off on a sucker... in which case you should have a conscience problem