Today we'll talk about the electric side of things.
Sort out your parts to be cleaned. In this case dusty parts with an emphasis in this post given to those battery powered bits.
Take electric pieces and set them aside... these Golden Era (1987-89) electric elements should not be cleaned with water.
But what if the part gets dusty or grimy??? I'm a cleaner! I gotta clean.
First use a #2 soft bristle paint brush from Linzer or whoever for hard to reach spaces in between studs. I suggest Linzer because that's the only thing I could find at the local brick and mortar store.
And for a Hail Mary play use a 1/2 black bristle for grimy sections. Keep this to a minimum... it will leave scratches. This is your last ditch effort before invoking moisture... on second thought... let this be a warning... don't use this brush if you can avoid it.
If you're a kid reading this... the next part should be done with a parent present... and away from any heat source.
A scenario: You know those times you've been eating Siroopwafel (my favorite snack) and you just have a hankering to play with some electifyingly awesome Lego? Well good job... now your favorite model is all gooey. A paint brush won't fix this; time to get the gloves on.
If you do use moisture... you should only take a Q-tip and dab/wipe (Don't soak!) with Isopropyl alcohol and air dry the pieces.
A good adage: If it's Metal never meddle with the water and be sure to pass on Ethyl.
warning! Ethyl Alcohol is bad for kids and plastic, it's almost worse than that soapy dishwater, so unless you want a mess or toxic toys your last ditch weapon is only Isopropyl alcohol.
Given the state of my parts... I will use no alchohol today... but I have this handy for those pesky little scrapes and abrasions... (it's 50%...ok...nope nope nope) There's something better.
I suggest getting 91- 99% Isopropyl solution for electric bits. Water is our enemy when cleaning these electric bits if we want to keep them working long term, which we do.
Quality Choice ALCOHOL ISOPROPYL 91% 16OZ
I did a bad thing :( Let me re-iterate that the bristle brush is not your main brush of choice... those light scratch marks are new... whoops.
Ta-da! Good as used.
You're building a circut... one row is positive and the other is negative... so you must build across the narrow width of the battery brick or you won't complete the circuit. That or the light brick is dead. Don't throw them away... I'll discuss repairing dead light bricks another day.