Need Cleaner for Aluminum Engine Block

I'm looking for a cleaning solution for aluminum auto parts.

Specifically, I have a few aluminum engine blocks that have seen 15 years of oil and radiator fluid, which has stained the surfaces of the interior channels.

In this case, mild etching during cleaning is acceptable, as the parts will not be re-used. They are being cleaned for display.

Rebuilders clean old aluminum blocks and heads by the use of high temperature (600 °F?). If there's one near you, they may do it for a nominal charge. It's difficult to clean aluminum of burnt on oil because the most effective cleaners are highly alkaline and will attack aluminum.

You can use next solution-- 50 gm citric acid ⇦ on eBay or Amazon [affil link] /1 lit water/+add some ammonia, pH must be 8,5.

bonami solution can be used too (30 gm/ 1 lit water).2-5% NaOH solution is another option (especially for oily and dirty surfaces,70-90 °C, 5-10 minutes,use rubber gloves ⇦ on eBay or Amazon [affil link] and safety goggles ⇦ on eBay or Amazon [affil link] ).Hope it helps and good luck!