Laptop cooling pads?

the ones i buy are 20-30 $$ and they work fine (i have several laptops)

Cooling pads are only going to cover the symptoms and are not a cure. Excess dust is unlikely in most household environments. If the laptop gets hot when being used on a desk or table, then we can rule out clothing blocking the vents and causing overheating. One cause of overheating I've seen is anti-virus software. If this is not set up correctly then it can cause the processor to run at 100%. This causes it to get hot, and gets the fan running at full-on, all the time. To check this you need to close programs such as games and office, go into the activity monitor and look at processor utilisation. If this is very high then you have a problem with stuff running in the background. This could be anti-virus, or some malware. You may need tech support to resolve the settings.

is there a need? the lap tops cooling systems are fine...just keep the intake and outlet clear and clean.

USB power will draw power from you battery.